The linked article is from Dec 2012 and it may have been discussed here at that time. If so, I must have missed it; I only recently heard someone refer to the subject.

http://www.sciencedaily.com/releases/2012/12/121211083212.htm

"Epigenetics -- how gene expression is regulated by temporary switches, called epi-marks -- appears to be a critical and overlooked factor contributing to the long-standing puzzle of why homosexuality occurs.

"According to the study, published online today in The Quarterly Review of Biology, sex-specific epi-marks, which normally do not pass between generations and are thus "erased," can lead to homosexuality when they escape erasure and are transmitted from father to daughter or mother to son.

"From an evolutionary standpoint, homosexuality is a trait that would not be expected to develop and persist in the face of Darwinian natural selection. Homosexuality is nevertheless common for men and women in most cultures. Previous studies have shown that homosexuality runs in families, leading most researchers to presume a genetic underpinning of sexual preference. However, no major gene for homosexuality has been found despite numerous studies searching for a genetic connection."

"Epi-marks constitute an extra layer of information attached to our genes' backbones that regulates their expression. While genes hold the instructions, epi-marks direct how those instructions are carried out".

"Sex-specific epi-marks produced in early fetal development protect each sex from the substantial natural variation in testosterone that occurs during later fetal development. Sex-specific epi-marks stop girl fetuses from being masculinized when they experience atypically high testosterone, and vice versa for boy fetuses. Different epi-marks protect different sex-specific traits from being masculinized or feminized -- some affect the genitals, others sexual identity, and yet others affect sexual partner preference. However, when these epi-marks are transmitted across generations from fathers to daughters or mothers to sons, they may cause reversed effects, such as the feminization of some traits in sons, such as sexual preference, and similarly a partial masculinization of daughters."

This next link is to the research posted on-line. I have yet to read through all of it, so I can't say much based on this link.

http://www.jstor.org/stable/10.1086/668167

This research is obviously a lie from Stan. Homosexuality is caused by the big M as taught by a prophet.

I read that report when it came out. I know a few sets of identical twins. In all cases but one set, the twins are either all gay or all straight. Epi-marks would explain the one outlying twin set I know.