A linkage between DNA markers on the X chromosome and male sexual orientation

The etiology of anomalous sexual preferences in men

People discover rather than choose their sexual interests. The process of discovery typically begins before the onset of puberty and is associated with an increase in the secretion of sex hormones from the adrenal glands. However, the determinants of the direction of sexual interest, in the sense of preferences for the same or opposite sex, are earlier. These preferences, although not manifest until much later in development, appear to be caused by the neural organizational effects of intrauterine hormonal events. Variations in these hormonal events likely have several causes and two of these appear to have been identified for males. One cause is genetic and the other involves the sensitization of the maternal immune system to some aspect of the male fetus. It is presently unclear how these two causes relate to each other. The most important question for future research is whether preferences for particular-aged partners and parts of the male courtship sequence share causes similar to those of erotic gender orientation.

Sex differences in the hypothalamus in the different stages of human life

Quite a number of structural and functional sex differences have been reported in the human hypothalamus and adjacent structures that may be related to not only reproduction, sexual orientation and gender identity, but also to the often pronounced sex differences in prevalence of psychiatric and neurological diseases. One of the recent focuses of interest in this respect is the possible beneficial effect of sex hormones on cognition in Alzheimer patients. The immunocytochemical localization of estrogen receptors (ER) alpha, beta and androgen receptors has shown that there are indeed numerous targets for sex hormones in the adult human brain. Observations in the infundibular nucleus have, however, indicated that in this brain area the hyperactivity resulting from a lack of estrogens in the menopause seems to protect females against Alzheimer changes, in contrast to males. It is thus quite possible that estrogen replacement therapy may, in these brain areas, lead to inhibition of neuronal metabolism and thus to the same proportion of Alzheimer changes as are observed in men. Knowledge about the functional sex differences in the brain and the effect of sex hormones on neuronal metabolism may thus provide clues not only for the possible beneficial effects of these hormones (e.g., on cognition or hypertension), but also on possible central side effects of estrogen replacement therapy.

"What are they going to do with the information?" Latino/Latina and African American perspectives on the Human Genome Project

New developments in genetic science raise questions regarding their application and implications. Dialogue about these questions has not often included the perspectives of the general population and, in particular, the voices of labeled racial or ethnic groups. In this article, the authors present results from an analysis of data from focus group discussions that engaged African Americans and Latinos/Latinas in a discussion of genetic research and technology. In particular, the authors focus on questions of inequality that arose in those focus groups and their implications for public health professionals interested in addressing pervasive racial disparities in health. In addition, they present strategies for achieving a more equitable distribution of risks and benefits from genetic research and technology suggested by participants in these focus groups.

Genetic basis of male sexual behavior

Male sexual behavior is increasingly the focus of genetic study in a variety of animals. Genetic analysis in the soil roundworm Caenorhabditis elegans and the fruit fly Drosophila melanogaster has lead to identification of genes and circuits that govern behaviors ranging from motivation and mate-searching to courtship and copulation. Some worm and fly genes have counterparts with related functions in higher animals and many more such correspondences can be expected. Analysis of mutations in mammals can potentially lead to insights into such issues as monogamous versus promiscuous sexual behavior and sexual orientation. Genetic analysis of sexual behavior has implications for understanding how the nervous system generates and controls a complex behavior. It can also help us to gain an appreciation of how behavior is encoded by genes and their regulatory sequences.

Cast into the wilderness: the impact of institutionalized religion on lesbians

SUMMARY This article addresses the impact of traditional Judeo-Christian religion as a tool of social injustice against lesbians. The prejudices of sexism and heterosexism in religion are addressed. Biblical interpretations of woman-to-woman sexuality are reviewed. Primary Judeo-Christian groups, and their respective positions on homosexuality, are identified. Conversion therapy as a weapon of oppression against lesbians is addressed. Mechanisms for religious/spiritual transformation and empowerment are discussed, and suggestions for therapeutic intervention with lesbians recovering from religious trauma are offered.

Androgens and male behavior

Sexual differentiation into a male or a female includes sexual differentiation of the brain. The paradigm of mammalian sexual differentiation is that in the presence of androgens (normally produced by the fetal testis) a male brain differentiation occurs, while in the absence of androgens (normal in females) a female brain differentiation follows. In the human there is a sex-dimorphism in gender identity/role, sexual orientation, sexual functioning, and in non-sexual functions, such as spatial ability, and verbal fluency. Inasmuch these properties can be studied in other mammals the effects of androgens are solidly demonstrable. In the human the evidence for androgen effects is equally plausible, evident from observations in subjects with errors in the process of sexual differentiation and in morphological studies of brain structures presumably related to these properties. But clinical observations show compellingly that other, largely unidentified, factors may modulate, or even override the effects of androgens.

Sexual differentiation of the brain: genes, estrogen, and neurotrophic factors

Based on evidence obtained during the past 50 years, the current hypothesis to explain the sexual dimorphism of structure and function in the brain of vertebrates maintains that these differences are produced by the epigenetic action of gonadal hormones. However, evidence has progressively accumulated suggesting that genetic mechanisms controlling sexual-specific neuronal characteristics precede, or occur in parallel with, hormonal effects. 1. In cultures of hypothalamic neurons taken from gestation day 16 (GD16) embryos, treatment of sexually segregated cultures with estradiol (E2) induces axon growth in neurons from male neurons, but not from female neurons. In these cultures treatment with E2 increased the levels of tyrosine kinase type B (TrkB) and insulin-like growth factor I (IGF-I) receptors in male but not in female neurons. This and other sex differences cannot be explained by differences in hormonal environment, because the donor embryos were obtained when gonadal secretion of steroids is just beginning, before the perinatal surge of testosterone that determines development of the male brain beginning at GD17/18. 2. The response to estrogen is contingent upon coculture with heterotopic glia (mostly astrocytes) from a target region (amygdala) harvested from same-sex fetuses at GD16, whereas in the presence of homotopic glia or in cultures without glia, E2 had no effect. It was concluded that the axogenic effect of E2 depends on interaction between neurons and glia from a target region and that neurons from fetal male donors appear to mature earlier than neurons from females, a differentiated response that takes place prior to divergent exposure to gonadal secretions. 3. The effects of target and nontarget glia-conditioned media (CM) on the E2-induced growth of neuronal processes of hypothalamic neurons obtained from sexually segregated fetal donors were also studied. Estrogen added to media conditioned by target glia modified the number of primary neurites and the growth of axons of hypothalamic neurons of males but not of females. 4. Neither the Type III steroidal receptor blocker tamoxifen nor Type I antiestrogen ICI 182,780 prevented the axogenic effects of the hormone. Estradiol made membrane-impermeable by conjugation to a protein of high molecular weight (E2-BSA) preserved its axogenic capacity, suggesting the possibility of a membrane effect responsible for the action of E2. 5. Western blot analysis of the tyrosine kinase type A (TrkA), type B (TrkB), type C (TrkC), and insulin-like growth factor (IGF-I R) receptors in extracts from homogenates of cultured hypothalamic neurons showed that in cultures of male-derived neurons grown with E2 and CM from target glia, the amounts of TrkB and IGF-I R increased notably. Densitometric quantification showed that these cultures had more TrkB than cultures with CM alone or E2 alone. On the contrary, in cultures of female-derived neurons, the presence of CM alone induced maximal levels of TrkB, which were not further increased by E2; female-derived neurons in all conditions did not contain IGF-I R. Levels of TrkC were not modified by any experimental condition in male- or female-derived cultures and Trk A was not found in the homogenates. These results are compared with similar data from other laboratories and integrated in a model for the confluent interaction of estrogen and neurotrophic factors released by glia that may contribute to the sexual differentiation of the brain.

The role of lay theories of the etiologies of homosexuality in attitudes towards lesbians and gay men

SUMMARY Previous research has demonstrated that those who believe that homosexuality is genetically or biologically caused have less negative attitudes towards gays and lesbians than those who believe it is acquired, learned, or chosen. This study, utilizing an undergraduate and graduate Psychology student sample, found significant relationships between attitudes towards lesbians and gay men and beliefs about causes and "treatments" for homosexuality. Level of personal contact with lesbians and gay men and demographic factors also influenced attitudes toward and beliefs about homosexuality. These results suggest that educational attempts to change attitudes towards lesbians and gay men should consider the role played by beliefs about the etiologies of homosexuality.

Sexual orientations in perspective

This article presents a new paradigm for understanding the complexity of human sexual, affectional, and erotic attractions--commonly known as sexual orientation. This new paradigm recognizes that there is great diversity among sexual orientations, erotic and emotional attractions, behaviors, and identities and that there are complex interrelations among these dimensions. Sexual orientation is determined by multiple influences, including a wide range of sociocultural factors. The development of sexual orientation is arrived at through multiple pathways. Individuals with the same sexual orientation may have little else in common. Thus, a model of sexual orientation is presented that is based on multiplicity, not sameness, and that examines the overlapping identities and statuses of culture, gender, age, race, ethnicity, class, disability, and sexuality.

Fraternal birth order and birth weight in probably prehomosexual feminine boys

The purpose of this study was to confirm a previous finding that homosexual males with older brothers weigh less at birth than do heterosexual males with older brothers. The subjects comprised 250 feminine boys referred to a child psychiatry service because of extreme cross-gender wishes or behavior and assumed, on the basis of previous research, to be prehomosexual, plus 739 control boys and 261 control girls referred to the same service for reasons unrelated to sexual orientation or gender identity disorder and assumed, from base-rate probabilities, to be preheterosexual. The feminine boys with two or more older brothers weighed 385 g less at birth than did the control boys with two or more older brothers (P = 0.005). In contrast, the feminine and control boys with fewer than two older brothers did not differ in birth weight. This finding suggests that the mechanism by which older brothers increase the odds of homosexuality in later-born males operates prior to the individual's birth. We hypothesize that this mechanism may be immunologic, that antimale antibodies produced by human mothers in response to immunization by male fetuses could decrease the birth weight of subsequent male fetuses as well as increase their odds of homosexuality.

Statistics for nonparametric linkage analysis of X-linked traits in general pedigrees

We have compared the power of several allele-sharing statistics for "nonparametric" linkage analysis of X-linked traits in nuclear families and extended pedigrees. Our rationale was that, although several of these statistics have been implemented in popular software packages, there has been no formal evaluation of their relative power. Here, we evaluate the relative performance of five test statistics, including two new test statistics. We considered sibships of sizes two through four, four different extended pedigrees, 15 different genetic models (12 single-locus models and 3 two-locus models), and varying recombination fractions between the marker and the trait locus. We analytically estimated the sample sizes required for 80% power at a significance level of.001 and also used simulation methods to estimate power for a sample size of 10 families. We tried to identify statistics whose power was robust over a wide variety of models, with the idea that such statistics would be particularly useful for detection of X-linked loci associated with complex traits. We found that a commonly used statistic, S(all), generally performed well under various conditions and had close to the optimal sample sizes in most cases but that there were certain cases in which it performed quite poorly. Our two new statistics did not perform any better than those already in the literature. We also note that, under dominant and additive models, regardless of the statistic used, pedigrees with all-female siblings have very little power to detect X-linked loci.

The paraphilic and hypersexual disorders: an overview

In this article, the first of a two-part series, the authors present reasons for considering the paraphilic and hypersexual disorders together and provide an overview of these disorders. The DSM-IV diagnostic criteria for paraphilias are reviewed, and proposed criteria for hypersexual disorders are presented. The question of whether the paraphilic and hypersexual disorders should be considered within the spectrum of obsessive-compulsive disorders is considered. The authors then review the epidemiology of these disorders, and discuss some implications of recent sexual predator legislation. The authors discuss the etiology of the paraphilias and hypersexual disorders, and consider the role of endocrinological function, findings from brain imaging and neuropsychological testing, findings from primate research, the monoamine hypothesis, the imprinting hypothesis, social learning theory, the concept of courtship disorder, the role of obsessive-compulsive elements, psychodynamic theories, and genetic factors. The phenomenology of the paraphilias and hypersexual disorders is discussed, including the tendency for multiple paraphilias to co-occur, the lack of a specific offender profile, the predominance of males among those with paraphilias, the incidence of a history of victimization in individuals with paraphilias and compulsive sexual disorders, the onset and course of both types of disorders, and the lack of internal motivation for change in individuals with paraphilias and hypersexual disorders. The authors then discuss disorders that commonly co-occur with paraphilias and compulsive sexual disorders, including mood disorders, substance abuse and dependence disorders, attention-deficit/hyperactivity disorder, anxiety and impulse control disorders, and personality disorders. The second article in the series will discuss the clinical assessment and the behavioral and psychopharmacological treatment of these disorders. A guide for clinicians and patients on where and how to find specialized clinicians and treatment resources in the United States will also be provided.

The interstitial nuclei of the human anterior hypothalamus: an investigation of variation with sex, sexual orientation, and HIV status

The interstitial nuclei of the human anterior hypothalamus (INAH1-4) have been considered candidates for homology with the sexually dimorphic nucleus of the preoptic area of the rat. Volumetric sexual dimorphism has been described for three of these nuclei (INAH1-3), and INAH3 has been reported to be smaller in homosexual than heterosexual men. The current study measured the INAH in Nissl-stained coronal sections in autopsy material from 34 presumed heterosexual men (24 HIV- and 10 HIV+), 34 presumed heterosexual women (25 HIV- and 9 HIV+), and 14 HIV+ homosexual men. HIV status significantly influenced the volume of INAH1 (8% larger in HIV+ heterosexual men and women relative to HIV- individuals), but no other INAH. INAH3 contained significantly more neurons and occupied a greater volume in presumed heterosexual males than females. No sex difference in volume was detected for any other INAH. No sexual variation in neuronal size or density was observed in any INAH. Although there was a trend for INAH3 to occupy a smaller volume in homosexual men than in heterosexual men, there was no difference in the number of neurons within the nucleus based on sexual orientation.

Fraternal birth order and the maternal immune hypothesis of male homosexuality

In men, sexual orientation correlates with an individual's number of older brothers, each additional older brother increasing the odds of homosexuality by approximately 33%. It has been hypothesized that this fraternal birth order effect reflects the progressive immunization of some mothers to Y-linked minor histocompatibility antigens (H-Y antigens) by each succeeding male fetus and the concomitantly increasing effects of such maternal immunization on the future sexual orientation of each succeeding male fetus. According to this hypothesis, anti-H-Y antibodies produced by the mother pass through the placental barrier to the fetus and affect aspects of sexual differentiation in the fetal brain. This explanation is consistent with a variety of evidence, including the apparent irrelevance of older sisters to the sexual orientation of later born males, the probable involvement of H-Y antigen in the development of sex-typical traits, and the detrimental effects of immunization of female mice to H-Y antigen on the reproductive performance of subsequent male offspring. The maternal immune hypothesis might also explain the recent finding that heterosexual males with older brothers weigh less at birth than heterosexual males with older sisters and homosexual males with older brothers weigh even less than heterosexual males with older brothers.

Genetic and environmental influences on human behavioral differences

Human behavioral genetic research aimed at characterizing the existence and nature of genetic and environmental influences on individual differences in cognitive ability, personality and interests, and psychopathology is reviewed. Twin and adoption studies indicate that most behavioral characteristics are heritable. Nonetheless, efforts to identify the genes influencing behavior have produced a limited number of confirmed linkages or associations. Behavioral genetic research also documents the importance of environmental factors, but contrary to the expectations of many behavioral scientists, the relevant environmental factors appear to be those that are not shared by reared together relatives. The observation of genotype-environment correlational processes and the hypothesized existence of genotype-environment interaction effects serve to distinguish behavioral traits from the medical and physiological phenotypes studied by human geneticists. Behavioral genetic research supports the heritability, not the genetic determination, of behavior.

Quantitative trait linkage mapping in anthropology

Recent years have seen rapid progress in several areas of both biomedical and anthropological genetics. While genetic analyses have come to play a significant role in biological anthropology, there has been little use of modern methods for linkage mapping of quantitative trait loci (QTLs). It is now feasible to design research studies to investigate the quantitative genetics of complex phenotypes that are of primary importance to traditional questions in biological anthropology. Complex traits such as functionally significant morphological features, physiological characteristics or aspects of behavior can be examined to estimate the influence of genetic variation on within-species phenotypic variation. In addition, new methods for mapping quantitative trait loci provide opportunities to identify the regions within chromosomes that contain the functional genes of interest. This review summarizes molecular genetic and statistical genetic approaches to QTL mapping, and presents examples of how this approach can expand the scope of anthropological genetics to include mapping and identifying individual genes that influence complex phenotypic traits relevant to fundamental questions in biological anthropology.

Sexual orientation beliefs: their relationship to anti-gay attitudes and biological determinist arguments

Previous studies which have measured beliefs about sexual orientation with either a single item, or a one-dimensional scale are discussed. In the present study beliefs were observed to vary along two dimensions: the "immutability" of sexual orientation and the "fundamentality" of a categorization of persons as heterosexuals and homosexuals. While conceptually related, these two dimensions were empirically distinct on several counts. They were negatively correlated with each other. Condemning attitudes toward lesbians and gay men were correlated positively with fundamentality but negatively with immutability. Immutability, but not fundamentality, affected the assimilation of a biological determinist argument. The relationship between sexual orientation beliefs and anti-gay prejudice is discussed and suggestions for empirical studies of sexual orientation beliefs are presented.

The ratio of 2nd to 4th digit length and male homosexuality

Sexual orientation may be influenced by prenatal levels of testosterone and oestrogen. There is evidence that the ratio of the length of 2nd and 4th digits (2D:4D) is negatively related to prenatal testosterone and positively to oestrogen. We report that (a) 2D:4D was lower in a sample of 88 homosexual men than in 88 sex- and age-matched controls recruited without regard to sexual orientation, (b) within the homosexual sample, there was a significant positive relationship between mean 2D:4D ratio and exclusive homosexuality, (c) overall, there was a decrease in 2D:4D from controls to homosexual men to bisexual men and (d) fraternal birth order, a positive predictor of male homosexuality, was not associated with 2D:4D in a sample of 240 Caucasian men recruited without regard to sexual orientation and 45 homosexual men.Further work is needed to confirm the relationships between 2D:4D and sexual orientation. However, these and other recent data tend to support an association between male homosexuality and high fetal testosterone. Very high testosterone levels may be associated with a sexual preference for both men and women.

Multipoint linkage analysis of the pseudoautosomal regions, using affected sibling pairs

Affected sibling pairs are often the design of choice in linkage-analysis studies with the goal of identifying the genes that increase susceptibility to complex diseases. Methods for multipoint analysis based on sibling amount of sharing that is identical by descent are widely available, for both autosomal and X-linked markers. Such methods have the advantage of making few assumptions about the mode of inheritance of the disease. However, with this approach, data from the pseudoautosomal regions on the X chromosome pose special challenges. Same-sex sibling pairs will share, in that region of the genome, more genetic material identical by descent, with and without the presence of a disease-susceptibility gene. This increased sharing will be more pronounced for markers closely linked to the sex-specific region. For the same reason, opposite-sex sibling pairs will share fewer alleles identical by descent. Failure to take this inequality in sharing into account may result in a false declaration of linkage if the study sample contains an excess of sex-concordant pairs, or a linkage may be missed when an excess of sex-discordant pairs is present. We propose a method to take into account this expected increase/decrease in sharing when markers in the pseudoautosomal region are analyzed. For quantitative traits, we demonstrate, using the Haseman-Elston method, (1) the same inflation in type I error, in the absence of an appropriate correction, and (2) the inadequacy of permutation tests to estimate levels of significance when all phenotypic values are permuted, irrespective of gender. The proposed method is illustrated with a genome screen on 350 sibling pairs affected with type I diabetes.

Sexual orientation and handedness in men and women: a meta-analysis

Recent findings suggest that sexual orientation has an early neurodevelopmental basis. Handedness, a behavioral marker of early neurodevelopment, has been associated with sexual orientation in some studies but not in others. The authors conducted a meta-analysis of 20 studies that compared the rates of non-right-handedness in 6,987 homosexual (6,182 men and 805 women) and 16,423 heterosexual (14,808 men and 1,615 women) participants. Homosexual participants had 39% greater odds of being non-right-handed. The corresponding values for homosexual men (20 contrasts) and women (9 contrasts) were 34% and 91%, respectively. The results support the notion that sexual orientation in some men and women has an early neurodevelopmental basis, but the factors responsible for the handedness-sexual orientation association require elucidation. The authors discuss 3 possibilities: cerebral laterality and prenatal exposure to sex hormones, maternal immunological reactions to the fetus, and developmental instability.

Analysis of the pseudoautosomal X-linked gene SYBL1in bipolar affective disorder: description of a new candidate allele for psychiatric disorders

The absence of father-to-son transmission has been observed in a subset of families with bipolar disorder (BPD), suggestive of a susceptibility gene on the sex-linked portion of the X chromosome. This is supported by some genetic linkage studies that have provided evidence for a susceptibility locus near Xq28. We have analyzed one candidate gene on Xq28, SYBL1, which maps to the Xq pseudoautosomal region (PAR). SYBL1 encodes a member of the synaptobrevin family of proteins that is involved in synaptic vesicle docking and membrane transport. Genes in the PAR generally escape X-chromosome inactivation and have an active homolog on the Y chromosome, which would result in an increase in same-sex concordance in paternal transmitted traits. However, SYBL1 is neither expressed on the Y chromosome nor the inactive X chromosome and would therefore be expected to show typical sex-linked transmission. We have screened SYBL1 for mutations that could be tested as candidate alleles in the development of BPD. Following single-strand conformation polymorphism (SSCP) analysis and DNA sequencing, four single nucleotide polymorphisms were detected: a silent mutation at codon 108, two intron mutations without any obvious biological significance, and a G-->C transversion in the polypyrimidine tract at the 3' splice acceptor site preceding exon 8. This polymorphism, which creates a perfect 16/16 stretch of pyrimidines, was analyzed in 110 patients with BPD not selected for sex-linked transmission and 119 control subjects. The results show a statistical trend toward an increase in the frequency of the C allele in males with BPD but not females. Males: chi(2) = 3.46, 1 df, p =.06; Females: chi(2) =.20, 1 df, p =.66.

The phenomenon of claimed memories of previous lives: possible interpretations and importance

Several disorders or abnormalities observed in medicine and psychology are not explicable (or not fully explicable) by genetics and environmental influences, either alone or together. These include phobias and philias observed in early infancy, unusual play in childhood, homosexuality, gender identity disorder, a child's idea of having parents other than its own, differences in temperament manifested soon after birth, unusual birthmarks and their correspondence with wounds on a deceased person, unusual birth defects, and differences (physical and behavioral) between monozygotic twins. The hypothesis of previous lives can contribute to the further understanding of these phenomena.

The disparate maternal aunt-uncle ratio in male transsexuals: an explanation invoking genomic imprinting

A significant skewing in the sex ratio in favour of females has been reported for the families of homosexual men such that there are fewer maternal uncles than aunts. This finding is repeated for a large series of transsexual families in this study. Four hundred and seventeen male-to-female transsexuals and 96 female-to-male transsexuals were assessed. Male-to-female transsexuals have a significant excess of maternal aunts vs. uncles. No differences from the expected parity were found for female-to-male transsexuals or on the paternal side. A posited explanation for these findings invokes X inactivation and genes on the X chromosome that escape inactivation but may be imprinted. Our hypothesis incorporates the known familial traits in the families of homosexuals and transsexuals by way of retention of the grand parental epigenotype on the X chromosome. Generation one would be characterized by a failure to erase the paternal imprints on the paternal X chromosome. Daughters of this second generation would produce sons that are XpY and XmY. Since XpY expresses Xist, the X chromosome is silenced and half of the sons are lost at the earliest stages of pregnancy because of the normal requirement for paternal X expression in extra-embryonic tissues. Females survive by virtue of inheriting two X chromosomes, and therefore the possibility of X chromosome counting and choice during embryonic development. In generation three, sons inheriting the paternal X after its second passage through the female germline survive, but half would inherit the feminizing Xp imprinted genes. These genes could pre-dispose the sons to feminization and subsequent development of either homosexuality or transsexualism.

Same-sex attraction, drug injection and binge drinking among Australian adolescents

OBJECTIVE

To document the prevalence of same-sex attraction among students in years 10 and 12 in Australian Government high schools and to assess the association between same-sex attraction, binge drinking and drug injection.

METHOD

Cross-section survey by anonymous, self-administered questionnaire of 3,387 students in Years 10 and 12 of the Government school system in Australia.

RESULTS

Approximately 6% of respondents reported being currently attracted to members of their own sex. Being attracted to members of the same-sex was associated with more frequent binge drinking among boys and girls, and a three- to four-fold increase in the likelihood of reporting injecting drug use both over the lifetime and within the previous 12 months.

CONCLUSIONS

Adolescents attracted to members of the same-sex report engaging in elevated levels of health-limiting behaviours. There is an urgent need for further research to document the reasons for this. It is recommended that health promotion activities directed at moderating young people's drug and alcohol practices explicitly acknowledge the over-representation of same-sex attracted young people in their target audience.

New phylism theory and the homosexualization of the visualization of lust

Nature needs nurture is the paradigm that replaces nature versus nurture. Nature's determinants are phylismic, i.e. they belong to the person phylogenetically as a member of the species and are not individually fortuitous. Phylismically, in the human species, vision and contrectation supplant pheromones as procreative attractants. The primary visual attractant, the sexual body morphology of a potential partner, is in all likelihood hormonally encoded into the sexual brain in fetal and/or neonatal life. Should the prenatal or neonatal encoding of the visual attractant become transposed from the visual image of the body morphology of the other sex to that of the same sex, then the brain would be biased in subsequent development toward some degree or variation of homosexual or bisexual attraction.

British psychiatry and homosexuality

BACKGROUND

Opposition to homosexuality in Europe reached a crescendo in the 19th century. What had earlier been regarded as a vice evolved as a perversion or psychological illness. Official reviews of homosexuality as both an illness and (for men) a crime led to discrimination, inhumane treatments and shame, guilt and fear for gay men and lesbians. Only recently has homosexuality been removed from all international diagnostic glossaries.

AIMS

To review how British psychiatry has regarded homosexuality over the past century.

METHOD

Review of key publications on homosexuality in British psychiatry.

RESULTS

The literature on homosexuality reflects evolving theories on sexuality over the past century. The assumptions in psychoanalysis and the behavioural sciences that sexuality could be altered led to unscientific theory and practice.

CONCLUSIONS

Mental health professionals in Britain should be aware of the mistakes of the past. Only in that way can we prevent future excesses and heal the gulf between gay and lesbian patients and their psychiatrists.

Male homosexuality: absence of linkage to microsatellite markers at Xq28

Several lines of evidence have implicated genetic factors in homosexuality. The most compelling observation has been the report of genetic linkage of male homosexuality to microsatellite markers on the X chromosome. This observation warranted further study and confirmation. Sharing of alleles at position Xq28 was studied in 52 gay male sibling pairs from Canadian families. Four markers at Xq28 were analyzed (DXS1113, BGN, Factor 8, and DXS1108). Allele and haplotype sharing for these markers was not increased over expectation. These results do not support an X-linked gene underlying male homosexuality.

Biology and the future of psychoanalysis: a new intellectual framework for psychiatry revisited

The American Journal of Psychiatry has received a number of letters in response to my earlier "Framework" article (1). Some of these are reprinted elsewhere in this issue, and I have answered them briefly there. However, one issue raised by some letters deserves a more detailed answer, and that relates to whether biology is at all relevant to psychoanalysis. To my mind, this issue is so central to the future of psychoanalysis that it cannot be addressed with a brief comment. I therefore have written this article in an attempt to outline the importance of biology for the future of psychoanalysis.

An apparent excess of sex- and reproduction-related genes on the human X chromosome

We describe here the results of a search of Mendelian inheritance in man, GENDIAG and other sources which suggest that, in comparison with autosomes 1, 2, 3, 4 and 11, the X chromosome may contain a significantly higher number of sex- and reproduction-related (SRR) genes. A similar comparison between X-linked entries and a subset of randomly chosen entries from the remaining autosomes also indicates an excess of genes on the X chromosome with one or more mutations affecting sex determination (e.g. DAX1), sexual differentiation (e.g. androgen receptor) or reproduction (e.g. POF1). A possible reason for disproportionate occurrence of such genes on the X chromosome could be that, during evolution, the 'choice' of a particular pair of homomorphic chromosomes for specialization as sex chromosomes may be related to the number of such genes initially present in it or, since sex determination and sexual dimorphism are often gene dose-dependent processes, the number of such genes necessary to be regulated in a dose-dependent manner. Further analysis of these data shows that XAR, the region which has been added on to the short arm of the X chromosome subsequent to eutherian-marsupial divergence, has nearly as high a proportion of SRR genes as XCR, the conserved region of the X chromosome. These observations are consistent with current hypotheses on the evolution of sexually antagonistic traits on sex chromosomes and suggest that both XCR and XAR may have accumulated SRR traits relatively rapidly because of X linkage.

Homosexuality and the human genome project: private and public choices

Recent scientific research which offers evidence of genetic and biologic influence in homosexuality has created serious concerns. The intent of this article is to offer suggestions based in principles of bioethics in which perceived negative outcomes may be diminished and the positive qualities of the research enhanced. For a portion of the general population the concerns expressed in this article could be alleviated through public discussion and exposure to the findings and theories of the academic and scientific communities. For another portion of the population, however, additional safeguards against misuse of screening tests and somatic cell interventions may be advisable through efforts initiated by researchers themselves, general public policies, and additional medical policies. While these efforts are recommended as short term goals for the separate scientific and social paradigms of homosexuality, it is proposed that an equally important and related debate involves the subjects of disease, normality and the value of diversity. It is suggested that while it is imperative that the behavioral and biological sciences recognize the limitations of their separate approaches, the reductionist approach itself limits our understanding of what essentially are questions of attraction and relationships. In conclusion, homosexuality should be understood from the perspective of autonomy as every person's right to experience a full and meaningful life.

The homoerotic behavior that never evolved

The emerging field of evolutionary psychology provides fascinating new insights into many salient human behaviors, but homosexual behavior is not among these. The new field perpetuates old stereotypes, and useful evolutionary analysis of homosexual behavior is largely nonexistent. In this article, the treatment of homosexual behavior in the field of evolutionary psychology is reviewed, and the factors contributing to this treatment are identified. Recommendations are made to help foster the development of alternative evolutionary models of homosexual behavior.

A Crossover Interaction Between Sex, Sexual Orientation, and Handedness

The distribution of handedness scores was analysed in 1414 heterosexual, bisexual, and homosexual men and women. Hand preference was assessed by a questionnaire that distinguishes consistently right-handed from partially or completely left-handed individuals, and sexual orientation was measured by the Kinsey scales. As expected from population-based studies, heterosexual men were, on average, more left-handed than heterosexual women. By contrast, gay men were more right-handed than lesbians or heterosexual men, and lesbians were more left-handed than gay men or heterosexual women. This crossover interaction suggests that a common variable influences sex, sexual orientation, and hand preference.

Health and development of gay and lesbian youths: implications for HIV/AIDS

Health and behavioral issues of gay and lesbian adolescents have recently become a focus of research and interest. A well conceived framework within which to consider thoughtfully the uniqueness of problems faced by homosexual youths and the role of health-care providers is needed. The prevalence, sociocultural history, and theories of origin of the homosexual orientation (biologic, psychoanalytic, and social processes) as well as general issues in adolescent development (biologic, cognitive, and emotional) all contribute to the development of a comprehensive perspective through which better health care and education can be provided. Responsible sexual behavior, depression, and suicide are health-care issues that physicians must be sensitive to and address openly. Up to 50% of gay youths have "seriously contemplated," suicide and 25% are estimated to have attempted suicide, according to the literature. In one study, up to 38% of pediatricians were uncomfortable in caring for homosexual adolescents within their practice. Practical suggestions include reviewing the language in office information forms and brochures providing appropriate literature that demonstrates acceptance of homosexual and bisexual orientations, and avoiding heterosexist bias in questions inquiring about sexuality. Physicians have an opportunity to modify the health and psychosocial risks faced by gay and lesbian youths by restructuring professional settings and accepting broader responsibilities for raising community awareness.

Comparison of the auditory systems of heterosexuals and homosexuals: click-evoked otoacoustic emissions

Click-evoked otoacoustic emissions (CEOAEs) are echo-like waveforms emitted by normal-hearing cochleas in response to a brief transient. CEOAEs are known to be stronger in females than in males. In this experiment, the CEOAEs of homosexual and bisexual females were found to be intermediate to those of heterosexual females and heterosexual males. A parsimonious explanation is that the auditory systems of homosexual and bisexual females, and the brain structures responsible for their sexual orientation, have been partially masculinized by exposure to high levels of androgens prenatally. No difference in CEOAEs was observed between homosexual and heterosexual males.

Eugenics and genetic testing

Pressures to lower health-care costs remain an important stimulus to eugenic approaches. Prenatal diagnosis followed by abortion of affected fetuses has replaced sterilization as the major eugenic technique. Voluntary acceptance has replaced coercion, but subtle pressures undermine personal autonomy. The failure of the old eugenics to accurately predict who will have affected offspring virtually disappears when prenatal diagnosis is used to predict Mendelian disorders. However, when prenatal diagnosis is used to detect inherited susceptibilities to adult-onset, common, complex disorders, considerable uncertainty is inherent in the prediction. Intolerance and the resurgence of genetic determinism are current pressures for a eugenic approach. The increasing use of carrier screening (to identify those at risk of having affected offspring) and of prenatal diagnosis could itself generate intolerance for those who refuse the procedures. Genetic determinism deflects society from social action that would reduce the burden of disease far more than even the maximum use of eugenics.