What a great niche to carve out in writing.

You may find the book The Chalice & The Blade by Dr. Riane Eisler to be of interest on this subject.

Perhaps the Sheela Na Gig was representative of the (hidden gnostic) concept that the divine was represented through the acts of life and death. Human life does enter the material realms through the vulva after all. Once it was one of the mysteries. Now it is deemed grotesque and scary.

Yep, definitely check out that book if you have the time.