When viewing lesbian sex and straight sex, both the homophobic and the non-homophobic men showed increased penis circumference. For gay male sex, however, only the homophobic men showed heightened penis arousal.
Heterosexual men with the most anti-gay attitudes, when asked, reported not being sexually aroused by gay male sex videos. But, their penises reported otherwise.
Homophobic men were the most sexually aroused by gay male sex acts.
Just a note: I now know more about the "device" they use to measure male sexual arousal than I ever needed, or wanted, to.