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Biomedical subjects

R Blanchard

Publications and source records attributed to R Blanchard.

At least 37 records · Page 2Linked to original sources
PubMed1998

Birth order in girls with gender identity disorder.

This study examined the birth order of girls with gender identity disorder (N = 22). Each proband was matched to 3-7 clinical control girls for age at assessment and number of siblings (the mode number of controls per proband was 7) (total N = 147). The number of older brothers, older sisters, younger brothers, and younger sisters was recorded. Slater's birth order index showed that the probands were significantly more likely to be early born than were the controls. A modified Slater's index also compared the birth order of the probands and the controls only to their brothers (when they had one or more) and only to their sisters (when they had one or more). Compared to the controls, the probands were born early compared to their sisters, but not to their brothers. These findings are the inverse of two previous studies of boys with gender identity disorder, who were later born relative to clinical control boys, an effect that appeared to be accounted for primarily by being born later relative to older brothers, but not to older sisters.

Adolescent↗
PubMed1998

The relation of birth order to sexual orientation in men and women.

Homosexual men have a higher mean birth order than do heterosexual men, primarily because they have a greater number of older brothers. The purpose of this study was to determine whether the same difference occurs in homosexual vs heterosexual women. The probands were 964 homosexual and heterosexual, male and female volunteers, from whom birth order data were collected with self-administered questionnaires. The homosexual men had more older brothers than the heterosexual men, but they did not have more older sisters, younger brothers, or younger sisters. The homosexual women did not differ from the heterosexual women with regard to any class of sibling. These results are consistent with the hypothesis that the high birth order of homosexual men reflects the progressive immunization of certain mothers to H-Y antigen by succeeding male fetuses, and the increasing effects of H-Y antibodies on sexual differentiation of the brain in succeeding male fetuses.

Adult↗
PubMed1998

Birth order in homosexual versus heterosexual sex offenders against children, pubescents, and adults.

Homosexual men erotically attracted to physically mature partners typically have more older brothers than comparable heterosexual men. We investigated whether late fraternal birth positions also occur in homosexuals attracted to children or pubescents. Probands were 710 sex offenders from Gebhard et al.'s (1965) study of sexual offending. Homosexual offenders against adults and pubescents had later fraternal birth positions than heterosexual offenders against adults and pubescents, respectively; there was no difference between the homosexual and heterosexual offenders against children. Results provide some evidence that homosexuality in men attracted to immature males is etiologically related to homosexuality in men attracted to mature males.

Adolescent↗
PubMed1998

Birth order and male homosexuality: extension of Slater's index.

Homosexual men tend to be later-born children. Slater's index, the ratio of older sibs to all sibs, is consistently higher for male homosexuals than for comparable heterosexuals. According to some explanations of this tendency, homosexual men are later born with respect to their brothers and later born with respect to their sisters only secondarily and less strongly. We show that if sisters have no direct bearing on a brother's sexual orientation and brothers do, then [formula: see text] On the other hand, if sisters have the same bearing on a brother's sexual orientation as male sibs do, then [formula: see text] These ratios are calculated and compared in nine samples of homosexual men and nine corresponding samples of control heterosexuals. The first equation holds for homosexual men, and the second equation holds for heterosexual men. The late birth order of homosexual men is sex specific. What matters is a boy's birth order relative to his brothers only. This effect may have its origins in an immune reaction or in behavioral contagion.

Analysis of Variance↗
PubMed1997

H-Y antigen and homosexuality in men.

In men, sexual orientation correlates with the number of older brothers, each additional older brother increasing the odds of homosexuality by approximately 33%. It is hypothesized that this fraternal birth order effect reflects the progressive immunization of some mothers to Y-linked minor histocompatibility antigens (H-Y antigen) by each succeeding male fetus, and the concomitantly increasing effects of H-Y antibodies on the sexual differentiation of the brain in each succeeding male fetus. This hypothesis 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.

Animals↗
PubMed1997

The relation of closed birth intervals to the sex of the preceding child and the sexual orientation of the succeeding child.

The study investigated whether homosexual men are, on average, born a shorter time after their next-older siblings than are heterosexual men. Because of mixed evidence that birth intervals are longer after a male child, the sex of the next-older sibling was included as a control variable. The probands were 220 heterosexual and 183 homosexual men with at least one older sibling examined in Southern Ontario in 1994-95. These completed a self-administered, anonymous questionnaire concerning their family background and other biodemographic information. The results showed that birth interval was negatively correlated with sibship size, positively correlated with maternal age, and uncorrelated with paternal age. They also confirmed that birth intervals are longer after a male than after a female child. The mean birth intervals preceding heterosexual and homosexual males, however, were virtually identical, indicating that the association of short birth intervals with decreased sex hormone levels in cord blood is unrelated to the development of sexual orientation.

Adolescent↗
PubMed1997

Additive effects of older brothers and homosexual brothers in the prediction of marriage and cohabitation.

Research has shown that male homosexuality tends to cluster in families and that homosexual males have, on average, a greater number of older brothers than do heterosexual males. This study investigated whether the former, between-families effect and the latter, within-families effect are additive. The subjects were 717 full siblings over age 40 reported by 343 heterosexual and homosexual male probands examined in Southern Ontario in 1994-1995. The sibling's history of legal marriage or cohabitation in a heterosexual relationship was taken as a proxy variable for sexual orientation. There were no significant findings for the female siblings. As expected, the never-married male siblings were more likely to come from the sibships of the homosexual probands, and they had a greater average number of older brothers. A bootstrapped logistic regression analysis showed that an additive model best explained the male siblings' data. The results suggest that the familial aggregation of male homosexuality cannot be explained by the birth order effect and that older brothers and family membership reflect separate influences on sexual orientation or sexual orientation-correlated behavior.

Adult↗
PubMed1997

Pedophilia, sexual orientation, and birth order.

This study extended research on birth order and erotic preferences by examining birth order in a sample of pedophiles. Charts of 338 pedophiles, assessed from 1980-1994 in the Behavioural Sexology Department of the Clarke Institute of Psychiatry in Toronto, were reviewed for family-demographic information. In total, 170 (57 heterosexual pedophiles, 68 homosexual pedophiles, and 45 bisexual pedophiles) of these men had sufficient sibling information to be included in the analyses. The results indicated that homosexual-bisexual pedophiles had a later birth order than heterosexual pedophiles and that this effect was primarily the result of the homosexual-bisexual group being born later among their brothers. The results extend previous findings that homosexual men, regardless of sample composition, have a later birth order than comparable groups of heterosexual men. The results also challenge some existing theories on the nature and origins of pedophilia.

Adolescent↗
PubMed1997

Sibling sex ratio of boys with gender identity disorder.

Sibling sex ratio (the ratio of brothers to sisters) was calculated for 444 boys with gender identity disorder (or with behaviors consistent with this diagnosis). The probands were ascertained from several researchers with expertise with this disorder and from the English language case report literature between 1938 and 1995. Among the probands with at least one sibling (N = 333), the results showed that boys with gender identity disorder had a significant excess of brothers to sisters, 131.1:100, when compared with the expected secondary sex ratio of 106:100. The excess of brothers replicated a previous study by Blanchard, Zucker, Bradley, and Hume (1995), in which the sibling sex ratio was 140.6:100. Further analyses showed that the probands were born later relative to their brothers than they were relative to their sisters. These findings are amenable to several psychosocial and biological explanations, which require further investigation.

Child↗
PubMed1996

Birth order and sibling sex ratio in two samples of Dutch gender-dysphoric homosexual males.

Two studies were undertaken to confirm the previous findings that homosexual men in general tend to have a later than expected birth order and that extremely feminine homosexual men also tend to have a higher than expected proportion of brothers (i.e., a higher sibling sex ratio). Subjects in Study 1 were Dutch, adult and adolescent, biological male patients with gender dysphoria (persistent and recurrent desires to belong to the opposite sex), who were undergoing treatment with feminizing hormones. These comprised 83 patients who reported sexual attraction to other males (the homosexual group) and 58 who reported sexual attraction to females or equal attraction to males and females (the non-homosexual group). Subjects in Study 2 were Dutch adolescent male patients at another hospital. The homosexual group consisted of 21 gender-dysphoric homosexual teenagers referred to a gender identity clinic for children and adolescents. The control group were 21 adolescent males referred to the child psychiatry department of the same hospital for reasons other than gender identity disorder, homosexuality, or transvestism. These were individually matched to the homosexual subjects on age and sibship size. In both studies, the homosexual group had a significantly later average birth order than the comparison group. In Study 1, the homosexual group had a significantly elevated sibling sex ratio; this was not tested in Study 2 because of its small sample size. These studies add to the mounting evidence that late birth orders are common to all homosexual samples and that elevated sibling sex ratios are an additional characteristic of extremely feminine ones.

Adolescent↗
PubMed1996

Handedness in homosexual and heterosexual men in the Kinsey interview data.

The relationship between sexual orientation and handedness in a large sample of men was examined. Subjects were 6544 nondelinquent men interviewed by the Kinsey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. Subjects were classified as either homosexual (n = 1004) or heterosexual (n = 4579). Results failed to demonstrate a difference in handedness, with both groups having rates of non-right-handedness (i.e., 11-12%) approximately equal to establish norms. These findings do not replicate some recent studies indicating an increased level of non-right-handedness in homosexual men.

Functional Laterality↗
PubMed1996

Biodemographic comparisons of homosexual and heterosexual men in the Kinsey Interview Data.

Relations between sexual orientation and several biodemographic variables previously reported to differentiate between homosexual and heterosexual men were examined. Subjects were 4948 white, postpubertal males, who were never reared in foster homes, orphanages, or other institutions, and were never arrested or convicted on criminal charges. These were dichotomously classified as homosexual (n = 844) or heterosexual (n = 4104). Data came from survey interviews conducted by staff members of The Kinesey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. Results extended previous findings that, compared with heterosexual controls, homosexual men have a later birth order, an earlier onset of puberty, and a lower body weight. Sexual orientation was weakly related or unrelated to height, paternal age, and sibling sex ratio. A more detailed analysis of the late birth order of the homosexual group showed that homosexual men have a greater number of older brothers than do heterosexual men, but they do not have a greater number of older sisters, once their number of older brothers has been taken into account.

Birth Order↗
PubMed1996

Prostitution advertisements suggest association of transvestism and masochism.

Previous research and clinical observation have suggested that the sexual interest of many transvestites include involvement in sadomasochistic sexual acts. Through data gathered via prostitution advertisements in print media, we tested the hypothesis that prostitutes welcoming cross-dressing client would be primarily those describing themselves as dominant. The specialty of the prostitute was recorded by coding the advertisements for the presence or absence of the features of dominance, submissiveness, acceptance of cross-dressing clients, and whether the prostitute was a biological male presenting as a woman or quasi-woman. The findings showed that 20% of prostitutes describing themselves as dominant welcomed cross-dressing clients, whereas none of the other subgroups of prostitutes mentioned cross-dressing clients in their advertisements. These findings reinforce other lines of indirect evidence suggesting that, in heterosexual men, the presence of masochism increases the likelihood of transvestism, and vice versa.

Advertising↗
PubMed1996

Homosexuality in men and number of older brothers.

OBJECTIVE: This study investigated whether homosexual men have a higher mean birth order than heterosexual men primarily because they have more older brothers or because they have more older siblings of both sexes. METHOD: For the main analyses, 302 heterosexual men were individually matched on year of birth with an equal number of heterosexual men. Each completed a self-administered, anonymous questionnaire concerning family background and other biodemographic information. RESULTS: Logistic regression analysis showed that homosexuality was positively correlated with the proband's number of older brothers but not with older sisters, younger brothers, younger sisters, or parental age at the time of the proband's birth. Each additional older brother increased the odds of homosexuality by 33%. CONCLUSIONS: These results restrict the range of possible theories of the birth order phenomenon to those that can explain not only why older brothers increase the probability of homosexuality in later-born males but also why older sisters neither enhance this effect nor counteract it.

Adolescent↗
PubMed1996

Analysis of cholesteryl ester transfer activity in adipose tissue.

Transfer of cholesteryl ester (CE) between lipoproteins is mediated by a plasma glycoprotein called cholesteryl ester transfer protein (CETP) which plays an important role in reverse cholesterol transport between peripheral tissues and the liver. Adipose tissue is a major site of cholesterol storage and lipoprotein interactions. CE transfer activity in cultured adipose tissue from several species was analyzed by using a CE transfer assay in vitro. Significant amounts of CE transfer activity were detected in conditioned media of cultured adipose tissues from human, hamster and transgenic mice expressing CETP. The amount of CE transfer activity released from cultured adipose tissue varied among species and adipose regions. Monoclonal antibodies against human CETP (subclone TP2) inhibited CE transfer activity released from cultured adipose tissue of hamsters and CETP transgenic mice. CE transfer activity was also assayed in the aqueous phase of adipose tissue homogenates. Accumulation of CE transfer activity in the medium was associated with a reciprocal decrease in adipose tissue activity positively correlated to the amount of CETP mass in the conditioned medium and the aqueous phase of tissue homogenates from cultured hamster adipose tissue. The results of the present study indicate that the measurement of CE transfer activity in adipose tissue reliably characterizes the secretion and storage of CETP in adipose tissue.

Adipose Tissue↗
PubMed1995

Comparison of height and weight in homosexual versus nonhomosexual male gender dysphorics.

The authors' clinical impression that homosexual gender-dysphoric males are physically smaller than nonhomosexual gender-dysphoric males was tested. Subjects were 176 homosexual and 246 nonhomosexual male outpatients, ages 16 to 65, who complained of discontent with their biological sex. Compared with the nonhomosexual male gender dysphorics, the homosexual gender dysphorics were shorter, lighter, and lighter in proportion to their height. The homosexual gender dysphorics were also shorter than men in the general population, whereas the nonhomosexual gender dysphorics were not. The smaller physiques of homosexual gender-dysphoric men may partly explain the clinical observation that these patients are somewhat more successful in passing as women.

Adolescent↗