Argument: Homophobia stems from irrational fear of rape, subordination
Scott Bidstrup. "Gay Marriage: The Arguments and the Motives": "The base fear here is that of rape and a loss of control or masculine status. This is instinctual and goes right to the core of our being as primates. If you examine what happens in many animal species, especially displays of dominance in other primate species, dominance displays often have sexual overtones. When, for example, in many species of primates, a subordinate male is faced with aggression by a dominant male, the dominant male will bite the subordinate, causing him to squeal in pain, drop the food (or the female) and present his rump. This is an act of submission, and it is saying to the whole troupe that the subordinate is just that - subordinate.
It has been suggested that homophobia is an instinctual fear of being raped by someone that the homophobe regards as lower than him in status. And the notion that a gay man might rape him is an instinctual fear.
This happens in humans just as it does in other primates. It is the cause of homosexual rape in prisons. Prison rape is not an act of sex as much as it is an expression of dominance and a means of control. Nearly all of the men who aggressively rape other men in a prison setting actually revert to promiscuous heterosexual sex once they're on the outside.
So is this something straight men should fear from gay men? Well, relax, all you straight guys. You've nothing to worry about. The vast majority of gay men prefer sex in the same emotional setting you do as a straight man with a woman - as a part of the expression of love, affection and commitment. We're not out to rape you or force you into a subordinate position. The majority of gay men don't want sex with you because we're looking for the same thing in a sexual relationship that you do - the love and affection of a partner. Since we're not likely to get that from you, you're not desirable to us and you have nothing to fear from us. The small minority of us (and it's a very small minority) who enjoy sex with straight men understand your fears and are not going to have sex with you unless it's clearly and completely on a peer-to-peer basis and your requirement for full and complete consent and need for discretion is honored."