We have the tag maternity-leave which is used in 29 questions currently. This is definitely a useful tag, but it really only refers to leave taken by the mother who just gave birth. There are many countries and employers that also offer parental leave to fathers and adoptive parents, and logistically it's treated pretty much the same as maternity leave. Using the maternity leave tag for these situations simply just isn't accurate (e.g this question), which is why I'm suggesting a new tag.
Sounds reasonable. Maybe the tag-wiki for parental-leave could explain that this is both for maternal leave in the proper sense (i.e. leave for mothers before and after giving birth) and for parental leave (leave for parents to look after their children) - just for those who really know what is what :-).