“You cannot discriminate on the basis of sexual orientation”
Easy argument for this... Same sex stuff isn’t sex.
sexual intercourse; noun (Websters’s Concise Encyclopedia)
Act in which the male reproductive organ enters the female reproductive tract (see reproductive system). Various sexual activities (foreplay) lead to physiological changes that progress to orgasm (climax) and resolution (see sexual response). If it is completed, semen passes from the male into the female’s body. If conditions favour fertilization, a sperm joins with an egg, and pregnancy begins (see fertility; reproduction); contraception can prevent this. Intercourse with an unwilling female is rape. See also reproductive behaviour; sexuality, human; sexually transmitted disease.
So. sex between other than man and woman is no diferent that masturbation or using a dildo... You might be able to define it as foreplay, but nothing more.