GEN1473 … Nahmanides … said that “Sexual intercourse is holy and pure when carried on properly, in the proper time and with the proper intentions. No one should claim that it is ugly or unseemly. God forbid … In a similar vein, Rabbi Jacob Emden is cited as having said: “ … to us the sexual act is worthy, good and beneficial even to the soul. No other human activity compares with it; when performed with pure and clean intention it is certainly holy. There is nothing impure or defective about it, rather much exaltation … Thus, whereas Christian teaching promulgates that procreation is the sole purpose of marriage and sexual intercourse, Judaism requires that not only need procreation result from sex, but mutual pleasure is sufficient reason for the sex act.   There are at least six methods of contraception mentioned in the Bible and Talmud. The first of these is “coitus interruptus” which is unequivocally prohibited as stated by Maimonides Mishneh Torah, Hilkhot Issurei Bi’ah 21:18: “It is forbidden to expend semen to no purpose. Consequently, a man should not thresh within and ejaculate without … As for masturbators, not only do they commit a strictly forbidden act, but they are also excommunicated. Concerning them it is written, ‘Your hands are full of blood’ Isaiah 1:15, and it is regarded as equivalent to killing a human being.” A similar prohibition is found in Asheri Teshuvot ha-Rosh 33:3, and in Caro’s Shulhan Arukh (Even ha-Ezer 23:5) as well as in other codes of Jewish law.   The scriptural source upon which is based the prohibition of improper emission of seed is not clear, although many consider the act of Er and Onan [this verse, 7—10] to be the classic case of coitus interruptus. The Talmud, however, Yevamot 34b, views the act of Er and Onan as unnatural intercourse. Er wanted to preserve his wife’s beauty by preventing her from becoming pregnant, and Onan sought to frustrate the Levirate law. Other possible Biblical sources outlawing emission of seed for naught have been suggested. The Decalogue’s commandment against adultery is said to have wider application, perhaps to immorality in general. The generation destroyed by the great flood is thought to have been liquidated because of the sin of improper emission of seed. Others say that this cardinal sin in implied in the commandment to be fruitful and multiply.  Finally, states Feldman, the injunction (in Leviticus 18:6) against incest, literally, “immorality with one’s own flesh” (ish ish el kol she’er besaro) includes improper emission of seed.  Whether this offense is considered homicide of only immoral as self-defilement is also a matter of argumentation. The Zohar apparently epouses both reasons. Bringing forth semen in vain would also be prohibited if a man were to use a condom during intercourse, even if the sex act were performed in the natural way. Procurement of sperm for medical reasons (i.e., not in vain) is permitted under certain circumstances, such as sterility testing.   Since the commandment of procreation in Judaism rests primarily on the man, any contraceptive method employed by him such as coitus interruptus or the condom would be strictly prohibited because of the Onanite nature of these methods. Even in situations where contraception is permitted by Jewish law, such as for situations in which pregnancy might endanger the life of the mother, these methods are not allowable. ROSNER 90-1