My citations are going to be imprecise and my claims are going to be broad; I apologize for those issues in advance.
Reading Savage Love obsessively led to catching a couple of other books. If you'll allow me to summarize and hopefully not form a strawman, Dan Savage believes that men and women are biologically different in their interaction with their sexual orientation. Basically, he posits that women have a "superpower" that allows them to, at times, change their sexual orientation. On his podcast, he once mentioned (paraphrase) "every time I turn around, some lesbian I knew is fuckin' men again, or becoming a man." Also, he has said that though he knows many lesbian women who came out as transgendered and became men, few gay men he's known long term have become women. Another relevant fact is that there are roughly twice as many gay-identified men as lesbian-identified women.
Observing people and their sexualities made me think about the relative high rate of casual bisexual behavior among heterosexual women, compared with the abysmally low rate of the male equivalent. Dan Savage's explanation of this phenomenon is an appeal to biology. Mine is not.
Reading The Masculine Self made me understand masculinity as power Features of traditional masculinity, e.g. having sex with women, are also a way to wield power. In this way, assuming that women are dis-privileged in the realm of heterosexual sex, I think that casual bisexual behavior is a way to lay claim to some of the masculine privilege.
My analysis of the other situations proceeds about the same. Fewer lesbian identified women? It's because living permanently in that pairing lacks any masculine power. Less casual bisexual behavior in heterosexual men? It's because admitting sexual attractions to men is actually a disavowal of masculine privilege. There's more female-to-male transexuals and fewer MTFs? It's obvious to me, and made plain in The Masculine Self that men are punished more for out-role behavior.
My underlying assumption is that though biology generally and genetics in specific have huge effects on our sexuality and gender identification, some of the difference in the statistics about the sexes in terms of gender identity and sexual behavior are the result of the out-sized structure of socialization regarding masculine power.
I would actually love to argue this out and defend my position with academic detachment, because I'm not at all certain of it.
