My source is wikipedia.. but here it is.
If nothing else the image of Christopher Walken as Gabriel makes me goAccording to the Jewish Talmud (Niddah 30b), God sends an angel to each womb and teaches a baby all the wisdom that can be obtained. Just before the unborn baby comes out, the angel touches it between the upper lip and the nose and all that it has taught the baby is forgotten.
Commentaries on this particular story can be found in "What the Angel Taught you" by Rabbi Noah Weinberg and Yaakov Salomon (ISBN 1-57819-134-3).
Similarly, in other folk sayings, it is said that an angel "shushes" the baby in the womb, to stop it from talking about heaven, or to forget. Other stories say that it is an indent left by the finger of God. Still more say that it is the spot where the angel put his finger to "shush" the child after having told it a secret. (This was memorably referenced in the film The Prophecy by the arch-angel Gabriel (Christopher Walken).)