 People go to the house where the baby is, to taste something [there], and this [eating] is also [considered] a seudat mitzvah.The Taz, a major commentator on the Rema, finds the source for the Rema's statement in the Talmudic tractate of Niddah (30b).Here the Talmud states that while a baby develops within the womb, "he is taught the entire Torah.