Abstraction said:
Interestingly, as far as sexual identity goes, it seems that for men a lot of sexual identity is hardwired. You were either born gay or not, with very few in a middle range. So far, for women, they haven't found any hardwiring. Unless there is a new discovery, it seems that sexual preference for women is a matter of choice.
I highly doubt the first part - that sexual identity is only hardwired. One of the basic tenets of biology is that organisms are influenced not just by genetics, but by the environment around them, and the society they live in (which really is part of the environment, but whatever). Besides which, I know a few guys who are bi, one of whom is a good friend of mine.
I think that both men and women have more homosexual encounters than one might suspect at first glance. However, there's a huge societal pressure, especially against guys, to avoid talking, thinking, or even admitting that. Especially to themselves. Definitely don't forget that due to the predominantly male-oriented culture, lesbians are infinitely more tolerated.
Tangent: I think it's because, as someone intimated earlier, men don't really think of lesbians as only being with women. Rather, there's a certain degree of wish-fulfillment with regards to three-ways and other stuff that is more of a societal taboo than the missionary position. Additionally, most people's "experience" with lesbians tends to be because of porn, which is hardly a basis for realistic personalities. Also, since porn is more designed to appeal to men than women, so of course it alludes to the fact that a man could be there.
So, in short, I think said study is biased simply by societal taboo and pressure. Homosexuality amongst males is strongly discouraged, more so than women. Saying that it is hardwired makes it easier for men to discount any number of potential situations which make throw doubt as to their sexuality. Which is dumb, but people are usually insecure about themselves.