And the 5th Law (which I just made up): People are eager to attribute traits they find morally praiseworthy or acceptable (music, being gay) to genes & evolution. They resist such explanations for traits they wish didn't exist (violence, sex differences).
New study on homosexual behavior confirms the Fourth Law of Behavioral Genetics: Heritable traits are usually caused by a huge number of genes each with a tiny effect, not a single "Gene for X."
As with other behavioral traits such as personality, there is no single “gay gene.” Instead, same-sex sexual behavior appears to be influenced by perhaps hundreds or thousands of genes, each with tiny effects, according to new research.
New, giant genome-wide association study finds genes that explain up to 25% of same-sex behavior (though not sexual orientation, which would include a relative dispreference for heterosexual sex).
Genetics may explain up to 25% of same-sex behavior, giant analysis reveals: “For the first time we can say without a reasonable doubt that some genes do influence the propensity to have same-sex partners,” says psychologist Michael Bailey.
also has a nice headline: Genetics may explain up to 25% of same-sex behavior, giant analysis reveals.
Genetics may explain up to 25% of *why y’all are straight*, giant analysis reveals | Science | AAAS