It would be reasonable to change "birth -oviposition" to "live_birth" in my opinion. Egg-laying is just not the same, and not what I'm looking for when I type in "birth". The tag system distinguishes one type, why not the other?
EDIT: And while we're at it, can we decide whether birth implies young? I've seen birth posts both with and without "young" where the only "young" character would be the birthee in question.
Updated