New Evidence of Genetic Factors Influencing Sexual Orientation in Men: Female Fecundity Increase in the Maternal Line

@article{Iemmola2009NewEO,
  title={New Evidence of Genetic Factors Influencing Sexual Orientation in Men: Female Fecundity Increase in the Maternal Line},
  author={Francesca Iemmola and Andrea S. Camperio Ciani},
  journal={Archives of Sexual Behavior},
  year={2009},
  volume={38},
  pages={393-399}
}
There is a long-standing debate on the role of genetic factors influencing homosexuality because the presence of these factors contradicts the Darwinian prediction according to which natural selection should progressively eliminate the factors that reduce individual fecundity and fitness. Recently, however, Camperio Ciani, Corna, and Capiluppi (Proceedings of the Royal Society of London, Series B: Biological Sciences, 271, 2217–2221, 2004), comparing the family trees of homosexuals with… 
Sexually Antagonistic Selection in Human Male Homosexuality
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This work performs a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation.
Human homosexuality: a paradigmatic arena for sexually antagonistic selection?
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It is argued that multilocus, partially X-linked genetic factors undergoing sexually antagonistic selection that promote maternal female fecundity at the cost of occasional male offspring homosexuality are the best candidates capable of explaining the frequency, familial clustering, and pedigree asymmetries observed in HS male proband families.
Fecundity of Paternal and Maternal Non-Parental Female Relatives of Homosexual and Heterosexual Men
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It is suggested that the empirical support for kin selection and maternal effects cannot account for the low universal frequency and stability of the distribution of homosexuals, and data support an X-linked multi-locus sexually antagonistic hypothesis rather than an autosomal multi- locus overdominance hypothesis.
Genetic Influences on Male Homosexuality
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The author investigates the Darwinian dilemma as to why genetic factors that influence homosexual nonreproductive behaviour can be maintained in the population without disappearing as expected and suggests that the reduced fecundity of male homosexuals is balanced by the effect of the same genetic factors in the maternal line females, thus balancing the effects on fitness and maintaining male homosexuality in thepopulation.
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The findings suggest that if sexually antagonistic genetic factors that induce homosexuality in males exist, the factors might be maintained in the population by contributing to increased fecundity greater reproductive health, extraversion, and a generally relaxed attitude toward family and social values in females of the maternal line of homosexual men.
Possible Balancing Selection in Human Female Homosexuality
TLDR
The balanced fecundity in the homosexual females’ families may allow the trait to be maintained at a low-frequency equilibrium in the population.
Heterosexual Male Carriers Could Explain Persistence of Homosexuality in Men: Individual-Based Simulations of an X-Linked Inheritance Model
  • G. Chaladze
  • Biology, Medicine
    Archives of sexual behavior
  • 2016
TLDR
IBM suggests that male homosexuality can be maintained in a population at low and stable frequencies if roughly more thanHalf of the females and half of the males are carriers of genes that predispose the male to homosexuality.
Fertility in the Mothers of Firstborn Homosexual and Heterosexual Men
  • R. Blanchard
  • Psychology, Medicine
    Archives of sexual behavior
  • 2012
TLDR
The results directly contradicted the prediction of the balancing selection hypothesis and it is possible that mothers who produce a homosexual son at their first delivery include a biologically distinct subpopulation of mothers of homosexual sons.
Interfamily Conflict, Reproductive Success, and the Evolution of Male Homosexuality
In a preindustrial context, the mate choices of women are controlled by their parents, who require evidence of wealth and of ability to generate wealth from prospective sons-in-law in order to grant
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References

SHOWING 1-10 OF 57 REFERENCES
Sexually Antagonistic Selection in Human Male Homosexuality
TLDR
This work performs a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation.
Maternal Inheritance and Familial Fecundity Factors in Male Homosexuality
TLDR
The familial history of male homosexuality is examined, and the so-called “fertile female” hypothesis for this trait in a contemporary British sample is tested, to find that white and non-white homosexual men had a significant excess of maternal but not paternal line male homosexual relatives compared to heterosexual men.
A linkage between DNA markers on the X chromosome and male sexual orientation.
TLDR
Investigation of pedigree and linkage analyses on 114 families of homosexual men found increased rates of same-sex orientation were found in the maternal uncles and male cousins of these subjects, but not in their fathers or paternal relatives, suggesting the possibility of sex-linked transmission in a portion of the population.
Evidence for maternally inherited factors favouring male homosexuality and promoting female fecundity
TLDR
The study confirms previous reports, in particular that homosexuals have more maternal than paternal male homosexual relatives, that homosexual males are more often later-born than first–born and that they have more older brothers than older sisters.
A Family History Study of Male Sexual Orientation Using Three Independent Samples
TLDR
The results differed significantly with those of some prior studies, but they do not exclude the possibility of moderate X-linkage for male sexual orientation, and the importance of familial factors for male homosexuality.
Genetic models of homosexuality: generating testable predictions
  • S. Gavrilets, W. Rice
  • Medicine, Biology
    Proceedings of the Royal Society B: Biological Sciences
  • 2006
TLDR
It is concluded that the measurement of the genetic characteristics of quantitative trait loci found in genomic screens for genes influencing homosexuality can be highly informative in resolving the form of natural selection maintaining their polymorphism.
A genetic study of male sexual orientation.
Homosexual male probands with monozygotic cotwins, dizygotic cotwins, or adoptive brothers were recruited using homophile publications. Sexual orientation of relatives was assessed either by asking
Homosexual behavior in primates: A review of evidence and theory
  • P. Vasey
  • Psychology
    International Journal of Primatology
  • 2007
Homosexual behavior is defined as genital contact, genital manipulation or both between same-sex individuals. Available data indicate that this behavior is phylogenetically widespread among the
A genomewide scan of male sexual orientation
TLDR
The results of this first genome screen for normal variation in the behavioral trait of sexual orientation in males should encourage efforts to replicate these findings in new samples with denser linkage maps in the suggested regions.
Kin selection and male androphilia in Samoan fa'afafine
Abstract The Kin Selection Hypothesis for male androphilia posits that genes for male androphilia can be maintained in the population if the fitness costs of not reproducing directly are offset by
...
1
2
3
4
5
...