Mellissa at Shakesville states that homophobia in men comes from the fear that [EDIT:] homosexual gay* men will treat them the same way that they treat women.

*According to the Gay & Lesbian Alliance Against Defamation (GLAAD), the use of ‘homosexual’ is offensive, and the term ‘gay’ in this case is preferred.

Offensive: “homosexual” (n. or adj.)
Preferred: “gay” (adj.); “gay man” or “lesbian” (n.)

Please use “lesbian” or “gay man” to describe people attracted to members of the same sex. Because of the clinical history of the word “homosexual,” it has been adopted by anti-gay extremists to suggest that lesbians and gay men are somehow diseased or psychologically/emotionally disordered — notions discredited by both the American Psychological Association and the American Psychiatric Association in the 1970s. Please avoid using “homosexual” except in direct quotes. Please also avoid using “homosexual” as a style variation simply to avoid repeated use of the word “gay.” The Associated Press, New York Times andWashington Post restrict usage of the term “homosexual” (See AP, New York Times & Washington Post Style).