Interesting post. Do you have a link to any of these studies?
Here is one study https://books.google.com/books?id=dASsUFtN57sC&pg=PA247&lpg=PA247&dq=lesbian+identical+twins&source=bl&ots=b4eksQB3Jj&sig=DBDb7CyPLP7A7m7h3N26vZH7iV4&hl=en&sa=X&ei=CY82VeeBPPiKsQTu4YGAAg&ved=0CD8Q6AEwBg#v=onepage&q=lesbian%20identical%20twins&f=false which supports the results, but note that except for ONE small sample, these are cases of twins raised together, not apart. So the environmental influence is not factored out. Nevertheless, even in these studies, you will see that twins are not invariably homosexual, even when raised in the same environment.
The small sample size lesbian study with identical twins raised separately again confirms: ABSOLUTELY 0 correlation. I am not aware of any study that has ever found a correlation.
In my own experience [which admittedly has a very small sample size] all six lesbians I've known personally arrived there after abusive relationships with men; and one of them subsequently even married a man after a 15 year lesbian "partnership."
riverdog; Here’s a place to start: How the APA “finding” that it’s all genetic is a “finding” that is not in any way “scientific.”
http://josephnicolosi.com/who-were-the-apa-task-force-me/