View Full Version : Genes and same sex behavior

30-08-19, 17:22
Well, they say they couldn't find "a" gay gene, but genetic variants account for 8-25% of the variation.

I'm not sure about this. In my experience you can just "tell" about some little boys, and it is contrary to what homosexual men themselves say about their sexual identity.


"Twin and family studies have shown that same-sex sexual behavior is partly geneticallyinfluenced, but previous searches for specific genes involved have been underpowered. Weperformed a genome-wide association study (GWAS) on 477,522 individuals, revealingfive loci significantly associated with same-sex sexual behavior. In aggregate, all testedgenetic variants accounted for 8 to 25% of variation in same-sex sexual behavior, onlypartially overlapped between males and females, and do not allow meaningful prediction ofan individual’s sexual behavior. Comparing these GWAS results with those for theproportion of same-sex to total number of sexual partners among nonheterosexualssuggests that there is no single continuum from opposite-sex to same-sex sexual behavior.Overall, our findings provide insights into the genetics underlying same-sex sexualbehavior and underscore the complexity of sexuality."

"In the UK Biobank sample, 4.1% of males and2.8% of females reported ever having had sexwith someone of the same sex (tables S1 and S2),with higher rates among younger participants(Fig. 1A)."

I would be more convinced if the question was are you exclusively homosexual.

"The discrepancy between the variance captured by the significant SNPsand all common SNPs suggests that same-sexsexual behavior, like most complex human traits,is influenced by the small, additive effects ofvery many genetic variants, most of which cannot be detected at the current sample size."

So, how do they know they have them all?

"Here, we highlightfindings relating to the two SNPs associatedwith male same-sex sexual behavior: rs34730029and rs28371400. First, the locus encompassingrs34730029-11q12.1 contains a number of olfactory receptor genes (several of which were significantly associated with same-sex sexual behaviorin a gene-based test) (fig. S6 and table S18). ThisSNP is correlated [linkage disequilibrium, coefficient of determination (R2) = 0.70] with amissense variant (rs6591536) in OR5A1 that hasbeen reported to have a substantial effect onthe sensitivity to certain scents (30). Second,rs28371400-15q21.3 had several indications ofbeing involved in sex hormone regulation: Theallele positively associated with same-sex sexualbehavior is associated with higher rate of malepattern balding [in which sex-hormone sensitivity is implicated (31)] and is located ~20 kbupstream of the TCF12 gene. TCF12 is the primary heterodimerization partner for TCF21, atranscription factor essential for normal development of the gonads in mice (32), and is involved inthe downstream actions of the SRY gene (which isresponsible for the initiation of male sex determination) in humans (33)."