I once worked with a chap who quite genuinely insisted he went to a gay bar, met 2 lesbians, had a threesome and turned them both straight.
Is it more likely that:
a) he was lying
b) he was lying and is also a massive ****
Actually that's not the question as the answer is obviously B, but do you ever meet men who actually believe the sheer force of their masculine virility will change your sexual preference?
Oh yeah. This sort of thing exists. Someone else asked "how do you tell men that hit on you that you're a lesbian," and the answer is I usually don't for this exact reason. Some men take it as a "okay time to try harder then" signal. (Good men are satisfied with a "no" at least).