I am very interested in the issue of paternal / maternal reasoning for descendency in our faith.
please can you detail how/when/why Hallacha became solely based on
matrilineal descent as deciding whether child jewish or not.
shalom
Greetings Richard,
The source for matrilineal determination of a child's Jewishness is based on the verses in Devarim (Deuteronomy 7:3-4, and 21:15), as described in tractate Kidushin (page 68b). (For the specific derivation in the verses, see our Outlines to the Daf to Kidushin 68b.) This is a precept that dates back to the giving of the Torah at Sinai.
As for the reasoning for why a child's Jewishness is determined by his mother, we can only speculate tentatively into the why's of the precepts of the Torah. It is logical to say that since only the motherhood of the child is provable without molecular microscopy, it is reasonable that the child's status is determined by the mother's (see also Sanhedrin 58b). There are deeper reasons related to this.
From the perspective of genetics, the concept of unilateral determination is not unfamiliar (as, for example, certain characteristics of a child (such as the gender) are determined solely by the chromosones contributed by the male, while other characteristics are determined solely by the female's chromosones)).
All the best,
Y. Shaw
D.A.F.
Jerusalem, Israel