It used to be true. In past gaming was privilege and not easy to get into. Consoles are still expensive that many people may not afford. Stereotypes often have hint of reality in it. They are stereotypes in times when surrounding changes. But as of now things have changed for gaming with small cost games being accessible for all.
This isn't quite true nowadays according to various data reports, as "gamers" or anyone who plays games, is almost at 50/50 male-female ratio, because of the rise of the smartphones as a "gaming" device, that's why games are much more accessible to everyone nowadays,
I do agree that this is a stereotype with no hint of truth to it. This is because gaming is more of an interest rather than a gender-based activity or hobby like say hunting. Girls are about as interested in gaming as guys are depending on exposure and availability of opportunities. Middle aged men and women also engage in gaming based on interests and exposure.