My most normal matriarchy idea is a society predicated on this belief:
Because women give birth, growing new life inside them and bringing it into the world' they are Goddesses. Each woman is a divine being, with men being seen as inferior creatures that only exist to aid in the process and serve the divine.
The male role in reproduction is heavily downplayed, and each guy is told that his mother only brought him into this world to serve Womenkind.