Levirate Marriage and the Family[ ]tween Ego and his wife and the marriage between the woman in ques-
tion and her husband (Ego’s father-in-law, the son of Ego’s mother-in-law
or father-in-law, stepson or stepgrandson).^119
Finally, the inquiry of Rav Mesharshia of Tusnia [J] raises the question
of extending prohibitions an additional generation upward, forbidding a
sexual relationship between Ego and his great-aunt or the wife of his great-
uncle. Ego is already prohibited from a relationship with his grandmother
or grandfather’s wife; the Bavli determines that this prohibition, itself an
extension, is not extended to include the grandparent’s siblings or sib-
lings’ spouses. The limit acknowledged here reflects not the generational
gap between these women and Ego, since an identical generational gap
exists between Ego and his grandmother, but the increasing degree of
separation between them. While the women in question are, technically
speaking, part of Ego’s family — one is a member of his patrilineage — their
connection does not justify an extension of the incest laws.
The question of a cutoff point for prohibited sexual relationships is
discussed in detail in the Yerushalmi:
a. It was taught: R. Hanin says: In all of these instances [listed in
the baraita], there is no cut-off point, except for the wife of the
father of his mother.
b. Bar Qappara says: In all of these instances, there is a cut-off
point. For Bar Qappara added [to the list]: the mother of the
father of his mother and the mother of the father of his father.
c. Rav said: In the instance of the daughter-in-law of his son, there
is a cut-off point.
d. What is the distinction?
e. The daughter-in-law of his son comes from a different source.
f. Rav said: Seed that derives from him is prohibited [regardless
of the number of generations between Ego and the individual
in question. But descendants of an in-law — presumably from
a relationship to an individual outside of Ego’s family — are not
prohibited].
g. R. Yose the son of R. Bun said: The reason of Rav is that [were
there no cut-off point for in-laws] Abraham would be forbidden
to all Jewish women and Sarah would be forbidden to all Jewish
men.^120