Ask the Rabbi

ear Rabbi Fried,
My wife and I, who are no spring chickens, were blessed with a baby girl three years ago, and are planning to attempt to have one more child. As we already have a girl, we would like to also have a boy. We know there are ways that modern medicine can assure, within a certain margin of error, the sex of the child. We just don’t know if morally, or within the parameters of Jewish laws of family purity, the methods used by doctors to do so are right and proper. We’d appreciate your guidance.
Marc and Sarah
Dear Marc and Sarah,
There are several methods of sexual pre-selection employed by physicians. One of the most reliable is to determine the sex of an unborn fetus by chromosome analysis of cultured amniotic fluid cells. If the fetus is not of the desired sex, it can be aborted. Judaism, however, unequivocally rejects the option of terminating a pregnancy simply because the fetus is not of the desired sex.
Another method of sex pre-selection involves procurement of semen from the prospective father, the separation of androsperm (for males) from gymnosperm (for females), and the artificial insemination of androsperm, if a male offspring is desired, into the prospective mother. This procedure results in a lower pregnancy rate than the insemination of the unseparated and less-manipulated semen, but yields about 70 percent male progeny. My mentor, the late Rav Shlomo Zalman Aurbach, did not allow this method of pre-selection. It was on the grounds of the prohibition of the active destruction of semen. Since the gymnosperm will be separated and destroyed, this would be prohibited. Only in the situation where the couple will be undergoing IVF in any case, and a pre-selection will anyway be necessary, might there be an allowance to perform such a pre-selection, upon consultation with an expert rabbinical authority in this area.
A third, less reliable, method of pre-selection has to do with the timing of relations. The proportion of male births is highest if they occur several days prior to ovulation. Since, however, you are observant of the laws of family purity (and I applaud you for that!), this method would be ruled out. In Jewish law, husband and wife are prohibited to have marital relations during the menstrual period and seven “clean” days thereafter, effectively eliminating this possibility from consideration.
A fourth method would be to manipulate the acidity and alkalinity of the cervical and vaginal secretions, as the male-producing sperm succumb to an acidic environment, and thrive in an environment of greater alkalinity. This would hold no prohibition in Jewish law, and would hold no negative moral implications. You would have to consult with your doctor as to the practicality of this method.
For more discussion on these methods, as well as methods mentioned in the Talmud, see Fred Rosner, M.D. in “Biomedical Ethics and Jewish Law,” Ktav Press, Ch. 14.
Since the minimum fulfillment of the mitzvah to “be fruitful and multiply” is explained by the Talmud to mean a son and daughter, there is not a moral issue with your pursuit of a son, which would complete this mitzvah for you. You are not, however, obligated to pursue such heroic methods to do so. The main thing is to pray for what you desire and for whatever you are blessed with to be healthy, and to accept joyously what the Almighty chooses to grant you.
Rabbi Yerachmiel D. Fried, noted scholar and author of numerous works on Jewish law, philosophy and Talmud, is founder and dean of DATA, the Dallas Kollel. Questions can be sent to him at

Leave a Reply