A particular version of the phobic theory of male homosexuality was tested, namely that homosexuality is based on an aversion against heterosexual intercourse.
In androphilic men, penile volume changes to verbal and written descriptions of the subjects' involvement in the various phases of heterosexual interaction were measured. Prior to each exposition of a verbal representation of such a phase, the subjects were prearoused by pictures of male nudes. Descriptions of involvement in the situation of locating a prospective female partner and of involvement in heterosexual pretactile interaction were responded to with penile detumescence that did not differ significantly from that to descriptions of involvement in sexually neutral situations. There was a further increase in penile volume of the prearoused subjects on descriptions of their involvement in heterosexual tactile interaction and intercourse.
These results contradict the hypothesis tested, whereas the subjects' verbal ratings of the various stimulus configurations on a disgust scale were in agreement with the phobic theory.
Freund K, Langevin R, Chamberlayne R, Deosoran A, Zajac Y. The Phobic Theory of Male Homosexuality. Arch Gen Psychiatry. 1974;31(4):495-499. doi:10.1001/archpsyc.1974.01760160045010