Reference for Chullin 139:27
אלא לאו כגון שיצא חציו ברוב אבר
What if She<span class="x" onmousemove="('comment',' The subject of the verb used is feminine whereas in the first question of Raba it is masculine. According to Rashi it refers to the woman who assists the delivery. She wrapped her hands around the foetus and thus extracted it so that there was no contact between the foetus and the u,zjt u,ujt womb of its dam. Tosaf. report a textual variant on the authority of R. Hananel; instead of 'she got hold of it' the reading is 'his sister'. The interpretation, accordingly, is this: there were twins within the womb, one male and the other female, and at the time of delivery it so happened that the female wrapped around and covered the male, so that there was no actual contact between the male twin and the womb.');"><sup>12</sup></span>