Fraternal Birth Order and Extreme Right-Handedness as Predictors of Sexual Orientation and Gender Nonconformity in Men

@article{Kishida2015FraternalBO,
  title={Fraternal Birth Order and Extreme Right-Handedness as Predictors of Sexual Orientation and Gender Nonconformity in Men},
  author={Mariana Kishida and Qazi Rahman},
  journal={Archives of Sexual Behavior},
  year={2015},
  volume={44},
  pages={1493-1501}
}
The present study explored whether there were relationships between number of older brothers, handedness, recalled childhood gender nonconformity (CGN), and sexual orientation in men. We used data from previous British studies conducted in our laboratory (N = 1,011 heterosexual men and 921 gay men). These men had completed measures of demographic variables, number and sex of siblings, CGN, and the Edinburgh Handedness Inventory. The results did not replicate the fraternal birth order effect… 

Fraternal Birth Order, Handedness, and Sexual Orientation in a Chinese Population

The results showed that homosexual women are more likely to be non-right-handed than heterosexual women, regardless of how sexual orientation was defined, whereas bisexual women areMore likely to been non- right-handedthan heterosexual women whenSexual orientation was assessed via sexual attraction and sexual identity.

Gender Nonconformity and Birth Order in Relation to Anal Sex Role Among Gay Men

The results suggest that the fraternal birth order effect may apply to a subset of gay men who have a bottom anal sex role preference and that this subgroup is more gender-nonconforming, but there were no significant associations between fraternalBirth order and gender nonconformity at the individual level.

Handedness and Birth Order Among Heterosexual Men, Gay Men, and Sao Praphet Song in Northern Thailand.

Sexual orientation and gender identity simultaneously is investigated simultaneously via comparison of 282 heterosexual men, 201 gay men, and 178 sao praphet song-i.e., androphilic, markedly feminine males recognized as a "third" gender in Thailand to provide new insights and replicate previous findings in a non-Western sample.

Handedness is a biomarker of variation in anal sex role behavior and Recalled Childhood Gender Nonconformity among gay men

It is suggested that developmental processes linked to handedness underpin variation among men in sexual orientation and gender nonconformity as well as variation among subgroups of gay men that are delineated by anal sex roles.

Multidimensional assessment of sexual orientation and the fraternal birth order effect.

Previous research demonstrates that for every older male sibling a male child has, the odds are increased by 33% over the naturally occurring odds that he will be nonheterosexual. This concept is

Associations of Bisexuality and Homosexuality with Handedness and Footedness: A Latent Variable Analysis Approach

The results were consistent with models of homosexuality that suggest a role of parental epigenetic marks on sexually dimorphic fetal development and research efforts should be increased with regard to footedness and epigenetic theories of homosexuality.

Fraternal Birth Order, Family Size, and Male Homosexuality: Meta-Analysis of Studies Spanning 25 Years

The fraternal birth order effect is the tendency for older brothers to increase the odds of homosexuality in later-born males and in homosexual subjects with masculine versus feminine gender identities is compared and evidence for the reliability of the effect was consistent.

Birth order and recalled childhood gender nonconformity in Samoan men and fa'afafine

No relationship was found between the number of older brothers a participant had and their recalled CGN, and these findings are consistent with previous studies suggesting that the FBO effect is associated with male sexual orientation, but not childhood female-typical gender expression among androphilic males.

The relationship between fraternal birth order and childhood sex-atypical behavior among the Istmo Zapotec muxes.

The results indicated that both cisgender muxe nguiiu and transgender muxe gunaa were more likely to be later born among brothers than gynephilic men, but the number of older brothers did not differentiate between transgender and cisgendermuxes, nor did it predict CSAB among muxes.

Increased birth rank of homosexual males: disentangling the older brother effect and sexual antagonism hypothesis

The theoretical and statistical tools to study FBOE and AE independently or in combination were developed and applied on new individual data, and on various available published data (two individual datasets, and all relevant aggregated data).

References

SHOWING 1-10 OF 84 REFERENCES

Extreme right-handedness, older brothers, and sexual orientation in men.

An elevated rate of extreme right-handedness was found in gay or bisexual men relative to heterosexual men, and it was demonstrated that older brothers moderate the relationship between handedness and sexual orientation.

Birth Order, Sibling Sex Ratio, Handedness, and Sexual Orientation of Male and Female Participants in a BBC Internet Research Project

The results yielded some evidence confirming prior findings that non-right-handedness is associated with homosexuality in men and women, that older brothers increase the odds of homosexuals in men, and that the effect of older brothers on sexual orientation is limited to right-handed men.

Gender Nonconformity, Intelligence, and Sexual Orientation

Data indicate a “sexuality-specific” effect on general cognitive ability but with limitations and support growing evidence that quantitative measures of sex-atypicality are useful in the study of trait sexual orientation.

Biodemographic comparisons of homosexual and heterosexual men in the kinsey interview data

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.

Biodemographic and Physical Correlates of Sexual Orientation in Men

It is found that the familiality for male sexual orientation decreased with relatedness, i.e., when moving from first-degree to second-degree relatives, and, contrary to some previous research, no evidence that maleSexual orientation is transmitted predominantly through the maternal line is found.

Family Size in White Gay and Heterosexual Men

The main outcome measure was the number of each man’s uncles and aunts, first cousins, siblings, nephews and nieces, and his own children, and increased fecundity in the relatives of gay men was found.

Birth order and sexual orientation in a national probability sample

The relations between birth order and sexual orientation in both men and women were examined in a national probability sample of the United States (Laumann, Gagnon, Michael, & Michaels, 1994). In

THE RELATION OF BIRTH ORDER TO SEXUAL ORIENTATION IN MEN AND WOMEN

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.

How Many Gay Men Owe Their Sexual Orientation to Fraternal Birth Order?

This work derived generalized forms of two epidemiological statistics, the attributable fraction and the population attributable fraction, which quantify the relationship between a condition and prior exposure to an agent that can cause it and showed that roughly 1 gay man in 7 owes his sexual orientation to the fraternal birth order effect.
...