AnkaraTheFallen said:
Not sexually attracted to guys at all so I can't imagine I'd like to see two guys having sex.... that said, I can't really understand why guys like to see two girls having sex. The only reason I can think of is subconsciously they think they might get to join in or something.
I've thought about this before, I think it's a biological thing that dates back to the early evolutionary days when sex was mostly for procreation (although some evidence suggests that we also did it for recreational and social bonding reasons as well). Monogamy was not inherent in early humans since it didn't really come about until we started our agricultural phase as the roles for men and women were required to become more fixed in early society. Early man would have similar behaviour to most other apes insomuch as they would have sex with multiple partners in order to spread larger amounts of their genetics. With this comes the requirement for territorial rights, so the sight of another male engaging in intercourse with a female that he has become aroused by will trigger a defense response to signify dominance.
Due to the fact that sex was a social and recreational activity in early man, the sight of two women engaging in sexual relations is far less likely to trigger a defense response since the females of our species were predominantly submissive in the social hierarchy, therefore the lack of another male would mean that there is no threat to defend against so the male would be less stressed and more likely to maintain arousal.
So, in today's society, the reason why lesbian pornography is so popular with males is because in girl x guy porn there is another male present (by "another" I mean that the male watching sees the male in the pornography as "another male"), which will lessen our arousal because we are conflicted between being aroused by the female, but not aroused (maybe even subconsciously threatened) by the "other" male which makes it less appealing to watch.
It's also why solo masturbation pornography is popular with males, simply because of the lack of that "other" male.
It's just a little theory of mine, but it makes sense. At least to me it does.