The ancient matriarchy is a discredited view that ancient human cultures were matriarchal. Some feminists claim that these ancient matriarchal cultures were taken over or defeated by aggressive patriarchal cultures and that evidence of the past matriarchy was systematically hidden by the patriarchy.
Some proponents of ancient matriarchies have claimed that ancient human cultures did not understand the connection between sexual intercourse and pregnancy. Modern research has completely debunked this. There are no known human cultures, today or in the past that did not know of the connection between sexual intercourse and pregnancy.
The notion of the ancient matriarchy was in fact invented by 19th-century European men and is a variant of the now-discredited (and generally regarded as racist) notion of the noble savage.
- Straight Dope