Edited Embryos, Designer Babies: Are They Kosher?

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08 Dec 2016
Torah in the City

Rabbi Gideon Weitzman, Director of the Puah Institute in the US and the Head of the English Speaking Section of the Puah Institute for Fertility and Medicine in Accordance with Halacha in Israel, will be speaking on January 15, 2017 at the OU’s Torah in the City event, indoors at Citi Field, on ‘Halacha: Are Edited Embryos Kosher? Pre-implantation diagnosis (PGD) in Jewish law.


Come to Torah in the City to hear more about this area of medicine and Jewish law — but for now, here’s a sneak peek of Rav Elyashiv’s take (written by Avraham Steinberg, translated from Hebrew by Rabbi Tzvi Hersh Weinreb):

Rabbi Yosef Shalom Elyashiv, zt”l, the supreme halachic authority in our generation, rendered halachic decisions on the use of some of the latest medical technologies as well as on other medical matters. I was privileged to raise various weighty questions with him on such topics. Below, I briefly discuss some of these questions and his halachic decisions, all of which I heard directly from him.

Preventing Genetic Defects

If both a husband and wife are carriers of the Tay-Sachs gene, even though they are perfectly healthy themselves, there is a 25 percent chance that they will have a child who will suffer from Tay-Sachs, a life-threatening disease. Due to recent advances in medical technology, it is possible to assist such a couple in preventing them from having a child with Tay-Sachs. This process—known as pre-implantation genetic diagnosis (PGD)—is achieved via in vitro fertilization (extracting a number of eggs from a woman and fertilizing them with her husband’s sperm outside the womb). A single cell is then extracted from each fertilized egg and analyzed to determine whether or not the gene for Tay-Sachs is present. Those eggs in which the gene is not present are then implanted in the mother’s womb to develop into a healthy fetus. Those eggs in which the Tay-Sachs gene is present are destroyed, thus preventing the birth of a child afflicted with this devastating illness. PGD can be employed for any disease for which the gene or faulty chromosome is known. Hundreds of disease genes have been identified to date.

Is PGD halachically permissible? According to Rav Elyashiv, it is permissible, and the destruction of the eggs in which the gene for the disease is present is permitted. What are possible rationales for this ruling? 1. An egg fertilized in vitro is not considered a human being, and indeed has no potential to develop into a full-fledged human being unless the egg is implanted in the woman’s womb; 2. A fertilized egg is at the stage of development that is halachically considered “within the first forty days of gestation.” According to our Sages, at such an early stage of development, the fetus is defined as mere fluid and is not considered a person with a soul.

Rav Elyashiv’s ruling would also permit stem cell experimentation using cells of fertilized eggs for the purpose of curing severe diseases. The fundamental principles justifying such experimentation are identical to those identified above: an egg fertilized outside the womb, and especially within the first forty days of development, is not considered a full-fledged human being; therefore, its destruction constitutes neither abortion nor murder.