Epigenetics is a fascinating field of study in evolution.
As to the phenomemon of queerness, they are postulating that:
~ sex-specific epi-marks passed from father to daughter or mother to son could cause homosexuality
~genes hold the instructions, epi-marks direct how those instructions are carried out – when, where and how much a gene is expressed during development. Epi-marks are usually produced anew each generation, but recent evidence demonstrates that they sometimes carry over between generations
~this usually happens in response to spikes in testosterone — sex-specific epi-marks formed in early fetal development activate to protect the fetus from the testosterone surge. Otherwise, the high testosterone could cause female fetuses to ‘masculinze’ or vice versa for male fetuses.
~different epi-marks protect different sex traits from being masculinized or feminized, some affect the genitals, others affect sexual identity and others affect sexual preference. But when epi-marks are transmitted 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.
~the transmission of sex-specific epi-marks between generations is the most plausible evolutionary mechanism of the phenomenon of human homosexuality
Theories are only as good as the thoughts behind them, and how those thoughts influence conclusions.
Seems to me, the thought behind this science is deeply rooted in stereotypical assumptions about queers i.e. gay females are masculinized and gay males are feminized.
The science could also be said to be steeped in the patriarchy. It is all testosterone based. Lord knows we have all been taught and socialized to believe ALL revolves around testosterone. Now, they are just looking for the bio-genetic proof.
On the other hand, as a feminist, it was also intriguing to see a defective testosterone process being targeted as the causal factor in this process 
However, I am sure it is just a matter of time before it will all link back to Adam, Eve, and that freakin apple.