Medical Halacha – Genetic Screening


Rabbi Yehuda Finchas 



Max and Michelle scratched their heads as they looked at each other in dismay. They are looking forward to getting married and having children and just discovered that it is recommended that they first do genetic screening.  “Rabbi, what should we do?” they asked. “We are both healthy, and this is causing us so much stress.”  


Genetic screening before marriage involves testing for specific genetic conditions that could be passed on to children.  On the one hand, receiving news of being a carrier of a genetic condition can cause distress for a condition that does not yet exist in a child who only might be affected by this disease. At the same time, knowing this information means that you can pro-actively take steps to prevent these diseases. For example, by doing in vitro fertilization with pre-implantation genetic diagnosis (PGD), we can ensure the selection of healthy embryos, and thereby prevent a specific genetic disease from being passed on to children. 


Rambam and Shulchan Aruch rule that caution is appropriate in choosing a future spouse and therefore, one should not marry into a family who are Mesoraim or Nichfim (Isurie Biah 21:3, S.A. EH 2:7 quoting Yevamot 64b). These cases are somewhat different than what we are dealing with, since the families mentioned have a known and established disease. In most cases, however, people do not know if they are a carrier of a genetic disease. Hacham Eliyahu Bakshi Doron (Responsa Binyan Av 5:65), discusses this at length and proposes principles and guidelines for finding the correct balance to screening.  


Genetic Screening Before Marriage 


Rav Bakshi starts by discussing testing for recessive genetic diseases, such as Tay-Sachs disease. A recessive trait means that for a child to be affected by the disorder both parents have to be carriers of the recessive gene. The parents are completely unaffected by the gene and each of their children has a 25 percent of being born with the disorder. He quotes Rabbi Moshe Feinstein, who permits genetic screening before marriage and argues that a person should not close their eyes to a common, deadly, and untreatable disease such as Tay-Sachs. 


There are, however, many genetic disorders. We do not test for all of them and it is difficult to know where to draw the line. Each community has its own risks and different prevalence of specific disorders. Ashkenazi Jews have higher prevalence of Tay-Sachs disease, Gaucher disease, and cystic fibrosis. Sephardic Jews more frequently are afflicted with Familial Mediterranean Fever, Machado Joseph Disease, or GSD. The specific frequencies will depend on if you are from North African, Persian, or Syrian descent.  


BRCA Mutation 


Hacham Bakshi then discusses whether an adult woman should test for BRCA mutations, which may mean that she will develop cancers later in life. He poses the dilemma as follows: Central to halacha is the principle of preserving life, VeNishmartem Me’od Lenafshotechem, and therefore, even if there is a small chance of a disease, one should be concerned about preventing it. If so, BRCA screening should be obligatory. Alternatively, at this point the woman is not ill, has no reason to believe that she will develop cancer, and perhaps there is no need to screen and “look into the future.” 


Hacham Bakshi explains that pikuach nefesh on Shabbat refers to situations when you are confronted with or can anticipate danger. He differentiates between an immediate danger – that permits desecrating even biblical Shabbat prohibitions – and situations in which there no threat or no danger at the moment, but only will arise in the future. For these latter cases, you may only desecrate rabbinic prohibitions to prevent the danger (Maran Beit Yosef OH 428 quoting Rabbenu Yerucham). 


Using this principle, Rav Bakshi distinguishes between a family who knows they have the BRCA mutation and those that have no reason to assume they have it. He rules that only a woman from a family with high chance of having this mutation is obligated to check for it. But if the statistical likelihood is small there is no obligation, and we should trust in Hashem and follow the instruction of “Tamim tehiyeh im Hashem Elokecha” (“walk simply with Hashem your Gd”). He explains that you are only expected to follow normal standard practice; doing too much hishtadlut may be problematic, too.  


In conclusion, there is not a one-size-fits-all approach, as each individual and community is different. Halachic authorities, geneticists, and physicians must work together to navigate the complexities of genetic screening and weigh up the risks and benefits tailored for each person. Undergoing PGD involves many questions and a posek should be consulted. 



Rabbi Yehuda Finchas is a worldwide expert, lecturer, and writer on medical halacha, and the head of the Torat Habayit Medical Halacha Institute. His latest book is entitled “Brain Death in Halacha and the Tower of Babel Syndrome.” To contact Rabbi Finchas, email