system
Given the following post, respond as if you're commenting on Reddit:
human
Why are straight males turned on by lesbian sex?

I know that it's a generalization and not all straight males are, but I think it's safe to say the vast majority of straight males, in the Western world at least, do find various sex acts by two women erotic.  Even just kissing.  And while some straight females feel the same about gay male sex, it's no where near as common.  So does anyone have a scientific explanation for this?  It seems counter-intuitive from the standpoint of passing on one's genes.
gpt
If you are going to answer this question, answer it with ***science***. Human sexuality is a well researched field with published experimental results. Layman speculation etc, is verbotten on askscience, we want scientific answers to these questions.