Psychoanalytic theory holds that homophobia -- the fear, anxiety, anger, discomfort and aversion that some ostensibly heterosexual people hold for gay individuals -- is the result of repressed homosexual urges that the person is either unaware of or denies. A study appearing in the August 1996 issue of the Journal of Abnormal Psychology, published by the American Psychological Association (APA), provides new empirical evidence that is consistent with that theory.  More:
http://www.apa.org/releases/homophob.html

Analysis of Homophobia
http://www.cyberpsych.org/homophobia/

Understanding Homophobia
http://psychology.ucdavis.edu/rainbow/html/homophobia.html

The Religious effect
http://www.religioustolerance.org/hom_fuel.htm

The simply answer is that some of us are not attracted to another man but the site of two women is even more attractive than one.  This is not necessarily "homophobia," unless someone is literally unwilling to touch another man (e.g., handshake).

The academic literature linkmeister linked to is probably more thoughtful than this answer.

-- Modified on 9/16/2001 9:01:50 AM

My dictionary defines homophobia as "irrational fear of, aversion to, or discrimination against homosexuality or homosexuals."  It is possible to not be physically attracted to other men but not care in the least what others are doing (as long as they aren't doing it in the street and frightening the horses, as someone -- I've forgotten who -- put it).

A long time ago I read a very interesting book about swinging.  I don't remember the author's name.  What I do remember was that he was an anthropology major and for his thesis got permission to study the swinging subculture.  One of the most interesting things that he found by observation (and that swingers never talked about) was that homosexual contact was almost universal among the women. (I think it usually occured after the men were exhausted and had ajourned to the kitchen to drink beer and talk about sports.)

I know at least two escorts who have told me that their favorite sexual fantasy is a three-way with two guys (and themself in the middle).  A porn film director (Henri Pachard) once said that you can only fantasize about what you haven't done.  Perhaps these very sexual women fantasize about this situation because they don't often get a chance to do it in real life.

Certainly my own experience is that guys recoil from the kind of situations that would involve getting naked in front of another guy even if there is a woman in the middle.

I've only ever been in this kind of three-way once (back in the mid 1970's).  The woman was a friend of my girfriend (who had been in a swinging relationship before her divorece).  The other guy was a good friend of mine who I trusted completely.  We had been through a number of adventures in the "human potentials" movement together.  Also, he was foreign born -- not a product of American culture.  Personally, I prefer a three-way with two ladies.  However, if the way this woman got off on the experience of having two guys at once is typical, perhaps we guys should be willing to broaden our horizons and try this kind of thing more often.