The article raises the question of changing sexual preference: Can a man whose past sexual practice has been almost exclusively heterosexual change his practice to homosexual after being seduced by another man? To those who believe that homosexual preference is homosexual orientation, an innate biological predisposition, the answer is a resounding 'no.' Contrary to this response, the author presents three cases in which the men switch from heterosexual to homosexual relationships (exclusively in two cases) by means of a sexual encounter initiated by another man.