Marrying One’s Niece

In the time of the Sages of the Talmud, it was considered a virtue and a mitzvah to marry one’s niece. However, nowadays it is proper not to marry one’s niece, because experience has shown that, God forbid, children born from such unions may have birth defects or mental health problems. This was likewise ruled by our master Rabbi Ovadia Yosef, of blessed memory, in his work Halichot Olam, vol. 7, p. 222: one who marries a close relative, the daughter of his brother or sister, should consult expert physicians and outstanding Torah scholars to determine whether there is any concern that the offspring may have defects.

In Otzar Niflaot HaTorah (Chayei Sarah, p. 363), the author testifies that he heard from our master Rabbi Chaim Kanievsky, may he live a long life, who spoke about the importance of observing the will of Rabbi Yehudah HaChasid in this matter. He related that there was a man who married his sister’s daughter, and they had two sons. After some time, both died unnatural deaths, Heaven forbid: one drowned in water and the other was burned in a fire, Heaven forbid. The bereaved father came to the illustrious Chazon Ish, of blessed memory, and asked him to explain the matter, since the Gemara states that it is a mitzvah to marry one’s niece. The Chazon Ish replied: It is true that the Gemara says this is a mitzvah, but that applied only until Rabbi Yehudah HaChasid, of blessed memory, said that one must be careful about this. Once Rabbi Yehudah HaChasid perceived through divine inspiration that it was dangerous, it was no longer a mitzvah.

Therefore, heed my advice: if you are not yet very old and there are other proposals available, pursue other matches. May it be God’s will that you soon merit to find your destined wife and, with good fortune and at an auspicious time, establish a faithful Jewish home founded upon Torah and reverence for God.