birthday?

[juxlus <pfly@NYX.CS.DU.EDU>]

a quick question, i realized the other day its difficult to say "birthday".
There is no gismu for "birth", although there is gutra for womb, which has
the note, "metaphorically for nourishing, birth, etc", but i feel sorta
clueless as to how one would use gutra as a basis for "birth".  And, even
beyond, "birthday", which really means something more like, "anniversary of
birth"...

slightly puzzled over this, someone care to enlighten me?  Thanks!

paul