Here's one - there are plenty more, however since I am not fixated on the subject of homosexuality (as some seem to be) - I don't have the time nor the inclination to post them all. You can Google as easily as I can.
One note of interest - the only sites that I can find that "debunk" the scientific studies are all religious sites that have an agenda to disprove any study that doesn't agree with their "homosexuality is a sin" viewpoint. Just because the Family Research Institue or Religious Tolerance.org or Christian Library.org all say these studies are wrong - does not make them wrong. Science is science and religion is religion. The same religion that says homosexuality is wrong also says that eating bacon is wrong or wearing a cotton/polyester blend is wrong. Ever eat a BLT??
"Research in Britain, America, and Germany has all confirmed that a prenatal exposure to deficiency of testosterone increases the likelihood of a man becoming homosexual. Men with an extra X chromosome and men exposed in the womb to female hormones are more likely to be gay or effeminate, and effeminate boys do indeed grow up to be gay more often than other boys. Intriquingly, men who were conceived and born in periods of great stress, such as toward the end of World War II, are more often gay than men born at other times. (The stress hormone cortisol is made from the same progenitor as testosterone; perhaps it uses us the raw material, leaving less to be made into testosterone.) The same is true of rats: Homosexual behavior is more common in rats whose mothers were stresses during pregnancy. The things that male brains are usually good at gay brains are often bad at, and vise versa. Gays are also more often left-handed than heterosexuals, which makes a sort of sense because handedness is affected by sex hormones during development, but it is also odd because left-handed people are supposed to be better at spatial tasks than right-handers. This only demonstrates how sketchy our knowledge still is of the relationship between genes, hormones, brains, and skills." (Ridley 1993: 264-5, The Red Queen)
None of these studies have been "debunked" - they have only been ignored.
Thank you for trying to support your position. That's more than most do when I challenge them to support their position. I can certainly understand time constraints and a lack of interest in a topic. And I just want to point out that you mentioned religious websites and the concept of sin. I did not and never do on this issue, unless somebody else brings it up first.
What you've posted is a paragraph from a book by Matt Ridley, but the full title to the book is The Red Queen: Sex and the Evolution of Human Nature. I've seen the paragraph before posted verbatim by others who I think pulled it from blogs or talk forums, which is what you may have done.
What you haven't done is posted a study or a reference to it that supports your position. I knew you couldn't when I challenged you to do so because there simply aren't any studies that support your position. In regards to "all the evidence that shows that homosexuality 'is genetic'?", Jeffrey Satinover says in The Gay Gene?:
There is not any, and none of the research itself claims there is; only the press and, sadly, certain researchers do-when speaking in sound bites to the public.I encourage you to read Satinover's article.