Sterilizing Animals
Sterilization, known as sirus in halacha, is any procedure that renders a person or animal incapable of reproduction. The prohibition against sterilizing animals is derived from the Torah. We are taught that only animals that are capable of reproduction are qualified to be offered as sacrifices.[1] Although there is some discussion on the matter, the prohibition against sterilization applies in both the Land of Israel as well as the Diaspora.[2]
As a general rule, one is forbidden to destroy or remove the reproductive organs of both humans and animals.[3] One who violated this prohibition and sterilized an animal is subject to the rabbinically imposed penalty of having to sell the animal so that one does not benefit from one’s transgression.[4] Even fish are included in the prohibition against sterilizing animals.[5] There is some discussion, however, whether sterilizing females is a biblical transgression[6] or a rabbinical one.[7] This is because females are not truly included in the mitzva of procreation.[8]
It is a matter of dispute whether non-Jews are included in the prohibition against sterilizing a living creature.[9] Although most halachic authorities rule that they are not included,[10] a number of authorities insist that they are.[11] As such, it is unclear whether a Jew may instruct or hire a non-Jewish veterinarian to sterilize an animal. According to the view that non-Jews are included in the prohibition against sterilizing animals, then it is certainly forbidden to ask a non-Jew to do so. In fact, asking a non-Jew to do so would also be a violation of “lifnei iver” the prohibition against causing or encouraging others to sin.[12]
According to the view that non-Jews are not included in the prohibition, and are therefore permitted to sterilize animals, it may be permitted to ask a non-Jew to do so. Some authorities are especially lenient regarding the sterilization of female animals if it is needed for the animal's benefit.[13] One is permitted to sell an animal to a non-Jew even though it is likely that the non-Jew will sterilize it.[14] There is even more room for leniency if the non-Jew who buys the animal arranges for another non-Jew to actually sterilize it.[15] Indeed, many authorities rule that one who must sterilize an animal should arrange for it to be transferred to a non-Jew who will then transfer it to another non-Jew to perform the sterilization procedure.[16] Due to the serious nature of the prohibition against sterilization, one who chooses to acquire a pet should acquire an animal that has already been neutered. In this way, one avoids the issue altogether.
It is interesting to note that halacha distinguishes between two different forms of sterilization: active and passive. The former refers to an act of sterilization that is performed directly upon the reproductive organs, which is generally forbidden. The latter refers to sterilization that occurs in a more indirect manner, such as by taking medication, which is often permitted. Indeed, the Talmud permits a woman to "drink the sterilizing potion" (which is the equivalent of today’s birth control pill) as a method of birth control when appropriate.[17] So too, there are different approaches among halachic authorities on the permissibility of temporary and reversible sterilization.[18]
[1] Vayikra 22:24.
[2] Torat Kohanim, Vayikra 22.
[3] Shabbat 110b; Chagiga 14b; EH 5:11.
[4] EH 5:14.
[5] Pitchei Teshuva, EH 5:8.
[6] Rambam, Hilchot Issurei Biah 16:11; Gra, EH 5:25.
[7] Chatam Sofer, EH 20; Arugot Habosem (Bachrach), EH 5:12; Igrot Moshe, EH 4:34.
[8] See Yashiv Yitzchak 10:36 at length.
[9] Sanhedrin 56b.
[10] Aruch Hashulchan, EH 5:26.
[11] Smag 120; Beit Shmuel, EH 5:16. See also Shevet Halevi 6:204.
[12] Vayikra 19:14.
[13] Turei Zahav, EH 5:6.
[14] Rema, EH 5:14.
[15] Terumat Hadeshen 299; Chatam Sofer, CM 185.
[16] Ha'elef Lecha Shlomo EH 23.
[17] Shabbat 110b, Rashi; Rambam, Hilchot Issurei Biah 16:11. For more on family planning see my “Halacha Bilvad”.
[18] Tzitz Eliezer 14:96; Minchat Yitzchak 3:26:1, 4:120; Devar Yehoshua 3:7.