Well, simple this is not. Some people can be made of "two" different DNAs. It basically happens that two embryos fuse making one health adult with two different DNAs, also known as a chimera.

If such a man has mixed sperm, meaning that some sperm is "his" and some are from a "melted, merged, mixed-in" brother. What happens to the children, for example, if some are born with DNA 1 and others are born with DNA 2?

Also, what about a cohen in this situation?

In summary, what's the status of such a "man", "child" and "mother/wife", also, consider the case of a cohen born with such mix and his wife, is she "cheating on him" and or "having children from two different people" etc?

This is an article presenting a case that happened recently where paternity tests said the child was his "uncle's" etc

read the article

  • 1
    For what it's worth, it mentions in Sefer Brit Menucha in the beginning that this idea of making chimeras was the sin of the generation of Enosh. It is associated with the concept of forbidden mixtures, "kilayim" just like sha'atnez and mixing meat and milk. Commented Oct 26, 2015 at 21:17
  • Hey! Go Rabbeinu Tam! Vindication after a millennia! (Well, kinda)
    – user6591
    Commented Oct 26, 2015 at 23:16

1 Answer 1


The product of adulterous relations between a married Jewish woman and a Jewish man who is not her husband is a mamzer. Genetics shchmenetics.

(The more common question is the converse -- married woman gets donor sperm from a Jewish man who's not her husband. Rabbis Moshe Feinstein and Shlomo Zalman Auerbach ruled that's not a mamzer as there were no adulterous relations. Yoel Teitelbam, the Satmar Rebbe, disagreed strongly.)

  • IIRC Reb Yoel's issue was against using nonjewish sperm which is what Reb Moshe suggested to use.
    – user6591
    Commented Oct 26, 2015 at 23:15
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    Is your first paragraph meant to be consistent with the opinion of the Satmar Rav quoted in the second paragraph?
    – mevaqesh
    Commented Oct 26, 2015 at 23:57
  • The question seems to be that the sperm is from the husband but has "mixed DNA" which would not be considered. After all identical twins have the same DNA so a paternity test could not tell the difference. Commented Oct 27, 2015 at 6:50
  • @mevaqesh no. Rav Moshe says it's all about the act. It's the Satmar view that would muddy the waters. (And even then, I'd assume he'd say it's the act OR the biological components.)
    – Shalom
    Commented Oct 27, 2015 at 10:58
  • @user6591 non-Jewish sperm does away with the problem of someone growing up and unknowingly marrying a halachic relative. Any non-husband sperm would be "adultery" according to the Satmar; it's never adultery according to Rav Moshe. (And even with conventional adulterous relations, the child is only a mamzer if the father was Jewish.)
    – Shalom
    Commented Oct 27, 2015 at 11:02

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