I think, Mutterleib and Leib are pretty archaic. I think Leib is still in use in some idioms and dialects, but I haven't heard or read it used in ages.
As for genders and words, Wikipedia has an interesting list:
" Old English had two common words for "woman": þat wīf (neuter) and se wīfmann (masculine). (These words are the origins, respectively, of modern "wife" and "woman".)
German die Frau (feminine) and das Weib (neuter) both mean "the woman", though the latter is considered archaic for most purposes (although some people may use mein Weib in a jocular fashion in non-formal contexts, and Weiber is still used sometimes with a derogatory meaning).
Irish cailÃn "girl" is masculine, while stail "stallion" is feminine.
Scottish Gaelic boireannach "woman" is masculine.
Slovenian dekle "girl" is neuter, while its cognate dekla "maidservant" is feminine.
Swedish människa "human" is feminine; in proper Swedish the feminine pronoun is used to refer to människa regardless of natural gender, although this usage may sound overly formal today.
Spanish la gente "the people" is feminine, even if the collective term refers to a group of men.
"
I can see how the theory that grammatical gender has anything to do with hierarchy of natural genders is appealing, but I don't think it neccessarily stands up to scrutiny.
Really need to start reading more linguistics books again, have become a bit rusty.