The Psychoanalytic Roots of Homophobia

Using a penile plethysmograph (PPG), the following paper (summary here) reports that sexual arousal of homophobes is greater than in non-homophobes when viewing homosexual sex. They also tend to admit to far less arousal than the PPG reports. Could be just anxiety rather than suppressed homosexuality, but interesting nonetheless.

Adams, Henry E; Wright, Lester W. Jr; Lohr, Bethany. 1996. "Is Homophobia Associated With Homosexual Arousal?", in Journal of Abnormal Psychology, Vol. 105, Iss. 3, August 1996, pp. 440-445.

(Stumbled across this while reading up on the Daubert case, where PPG has had mixed success).