The main subject of Tractate Nidda is the ritual impurity of menstruating women. But women aren’t the only ones who can become tamei, impure, because of “issue” from the genitals. When a man has a seminal emission, he becomes tamei for the rest of the day, in accordance with the rule in Leviticus 15:16: “If a man has an emission of semen, he shall bathe his whole body in water, and be unclean until the evening.” Formally speaking, the parallel between menstruation and ejaculation makes a kind of sense: both have to do with fluids emerging from the genitals, and both are bound up with fertility and reproduction.
But in chapter two of Nidda, which initially focuses on ejaculation, it becomes clear that the two types of emission are seen very differently by the rabbis. Menstruation takes place automatically, whether a woman wants it to or not; and while it is obviously related to reproduction, it is not part of the sexual act or accompanied by sexual pleasure. Accordingly, the rabbis’ feeling toward it is basically neutral. No shame attaches to a woman for menstruating; it is simply a part of life that has to be reckoned with and brought under the domain of Jewish law.
Ejaculation, on the other hand, is seen by the rabbis as a very dangerous temptation for men, since it can be brought about deliberately by masturbation. Masturbation was traditionally known in English as onanism, after the story of Onan in Genesis: he was the son of Judah who refused to do his duty by Tamar, his dead brother’s wife, and “spilled his seed on the ground” rather than impregnate her. As this story shows, the Torah is very concerned about the waste of semen, which must be used solely for the purpose of procreation.
For that reason, in Nidda the rabbis build a “fence around the law” by establishing extraordinarily strict rules about how a Jewish man should handle his penis. For women, says the mishna in Nidda 13a, inspecting their genitals for signs of an emission is “praiseworthy,” but if a man does the same thing, his hand “should be severed.” The Gemara explains the reason for the difference: women, the rabbis believe, “are not susceptible to arousal” when they touch themselves, but men are, so that a man who spends too much time handling his penis may be irresistibly tempted to masturbate.
Here, as often in the Talmud, we see that the rabbis’ understanding of women’s bodies and sexuality was based largely on supposition—if they had asked an actual woman about it, or if women themselves could have been rabbis, they might have come to different conclusions. But even if a woman did masturbate, this would not have struck the rabbis as being nearly as dangerous as a man doing the same, because only men produce semen.
And wasting semen, the Gemara explains, is a sin with literally cosmic implications. According to Rabbi Yosei, “the Messiah, the son of David, will not come until all the souls of the body have been finished.” In other words, human souls preexist the bodies they come to inhabit at birth, and not until the whole heavenly supply of souls has been born can the world come to an end. When a man ejaculates in a way that could not lead to the birth of a child, he is throwing away an opportunity to bring one of these souls to earth, and so delaying the arrival of the Messiah.
This idea, which would be elaborated in the Zohar and the Jewish mystical tradition, helps to explain the sharply divided feelings of traditional Judaism about sex. Sex within marriage is warmly encouraged in the Talmud: husbands owe sexual gratification to their wives, and having sex is one of the best things a pious Jew can do on Shabbat. But according to Rabbi Yochanan, “anyone who emits semen for naught”—that is, in any non-reproductive sexual act—“is liable to receive death at the hand of Heaven,” just as Onan did.
To avoid the temptation to masturbate, then, the Talmud prohibits Jewish men from touching their own penises in any context. We have already seen that men should not use their hands to inspect themselves for seminal emissions. Instead, the Gemara in Nidda 13a says, they can use “a rock or a piece of earthenware” to scrape any fluid off their genitals—which doesn’t sound like a very appealing procedure.
Of more practical application is the rule that a man cannot touch his penis while urinating: according to Rabbi Eliezer, “anyone who holds his penis and urinates, it is considered as though he is bringing a flood into the world.” (There’s a double meaning here: the connection of urine with floodwaters, but also the idea that masturbation was one of the sins that led God to send the Flood in Noah’s time.) The rabbis made a very natural objection to Eliezer’s rule, which is that if a man can’t hold his penis while he urinates, he’s more likely to end up with “small drops sprayed on his legs.” To avoid this, Eliezer responds, a man should “stand on an elevated place and urinate downward.”
Other rabbis offer different possible approaches: Abba says that it is all right for a man to hold his testicles, just not the penis itself; Rabbi Yochanan says that he can hold the penis at the tip, but not touch the shaft. What’s important is that a man not even approach a condition where he might be tempted to ejaculate. Even “one who intentionally causes himself an erection,” Rav says, should be punished by ostracism. Rabbi Ami explains that erections are a gateway sin: once you start “arousing the evil inclination,” you’ll end up worshiping idols.
Still, the mishna’s original statement, that a man who touches his genitals should have his hand severed, strikes the rabbis of the Gemara as excessive. Was this meant literally, they ask, or is it just hyperbole, a “curse” meant to underline the seriousness of the rule? According to Rabbi Tarfon, however, the law means just what it says: “if one’s hand goes to his penis, his hand should be severed upon his navel.”
And what if, the Rabbis wonder, a man has a thorn stuck in his belly and will die unless he removes it: is he allowed to move his hand in the general direction of his penis in order to pluck out the thorn? Absolutely not, Tarfon replies: “It is preferable that his belly be split open, and he should not descend into the pit of destruction.” Such sayings show that sexual puritanism has deep roots in Judaism, and must have been responsible for a great deal of mental anguish over the centuries.