I organised chess tournaments for many years, mostly for children. In my experience, at the primary age it is about 35-40% female, but there is a huge drop-off in the teenage years.
The boys seem to be more willing to play in secondary school, but competitive chess is intellectually demanding, and as the boys start working towards a career, in seconday school and in university, chess becomes a recreational activity for most. Probably a good thing.
The world championship has two categories, last time I checked, "open" and "female". No woman has ever qualified for the open championship. As a previous poster said, only one woman has ever cracked the top 100 rating list, and she was very much an outlier.
Someone once said that women are too smart to play chess.