|"I don't remember people saying anything of the sort."
Were you living a sheltered life in the 90s? Or are you just not remembering?
You can do your own research (google is your friend, ya know) but for a head start, check out Ralph Reed, Jerry Falwell, Pat Robertson, et al. Just about any gay hater of the period trafficked in the idea, under one guise or another. And (as I mentioned earlier) conversion therapy is premised on just this fallacy. You can also follow discussions of genetics vs. environment. If you are not being disingenuous.