Re: K čemu jsou nám homosexuálové?

Ellííí, zřejmě narážíš mimo jiné na zmínku o X-vázané dědičnosti homosexuality, spjaté se zvýšenou ženskou plodností.

Nemůžu z domova k celým článkům, studií na to téma bylo víc, ale nemám, jak to tady dohledat. Zkopíruju Ti sem aspoň jeden abstrakt

New evidence of genetic factors influencing sexual orientation in men: female fecundity increase in the maternal line.

Iemmola F, Camperio Ciani A.

Department of General Psychology, University of Padova, via Belzoni 80, Padua, Italy.

Arch Sex Behav. 2009 Jun;38(3):393-9.


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 heterosexuals, reported a significant increase in fecundity
in the females related to the homosexual probands from the maternal line but not
in those related from the paternal one. This suggested that genetic factors that
are partly linked to the X-chromosome and that influence homosexual orientation
in males are not selected against because they increase fecundity in female
carriers, thus offering a solution to the Darwinian paradox and an explanation of
why natural selection does not progressively eliminate homosexuals. Since then,
new data have emerged suggesting not only an increase in maternal fecundity but
also larger paternal family sizes for homosexuals. These results are partly
conflicting and indicate the need for a replication on a wider sample with a
larger geographic distribution. This study examined the family trees of 250 male
probands, of which 152 were homosexuals. The results confirmed the study of
Camperio Ciani et al. (2004). We observed a significant fecundity increase even
in primiparous mothers, which was not evident in the previous study. No evidence
of increased paternal fecundity was found; thus, our data confirmed a sexually
antagonistic inheritance partly linked to the X-chromosome that promotes
fecundity in females and a homosexual sexual orientation in males.