הלכה אויף בראשית 30:21

The Aramaic Targum (translation of the Torah) attributed to Yonatan Ben Uzziel (Bereishit 30:21) cites a tradition that Rachel conceived and carried Dinah, while Leah conceived and carried Yosef. Leah prayed on Rachel’s behalf that she should give birth to a boy and thus be the mother of one of the tribes. God accepted Leah’s pleas on behalf of her sister and exchanged the two fetuses, so Leah’s womb carried Dinah and Rachel’s womb carried Yosef. Since the Torah records Leah as Dinah’s mother and Rachel as Yosef’s mother, one might conclude that according to this Targum, giving birth confers the status of motherhood.