Amazing. Not surprising. From Details April 2006 issue (Know + Tell section).
Read more here. The quote I like: "In tests conducted by Prof. Henry E Adams of the University of Georgia, homophobic men who said they were exclusively heterosexual were shown gay sex videos. Four out of five became sexually aroused by the homoerotic imagery, as recorded by a penile circumference measuring device - a plethysmograph. Prof. Adams says his research shows that most homophobes "demonstrate significant sexual arousal to homosexual erotic stimuli", suggesting that homophobia is a form of "latent homosexuality where persons are either unaware of or deny their homosexual urges"."
The original research was published in 1996! The author passed away, unfortunately. Get the full article at the APA web site (I thank aTypical Joe for the article). Nothing like an anal retentive magazine to bring up the subject again in 2006.