A blog post at Gallup, sent along by Michael Kimmel, discussed nearly 25 years of US opinion on the cause of homosexuality. The data shows a slow decline in the percent of people who think that people are “made” gay or lesbian by their upbringing or environment (the nurture argument) and a slow rise in the number of people who think they are “made” gay or lesbian by biology (the nature argument). The two meet in the late 1990s and, throughout the 2000s, they’ve been more-or-less neck-and-neck.
I welcome speculation as to why the trend didn’t continue such that nature ended up beating nurture good by 2010. I can’t think offhand of a reason why.