Bolded is inaccurate. As this guy says:
MMORPGs actually have a gender split closer to the RPG ratio versus MOBAs like LoL and DotA 2 which have the... ratio you see up there quoted by Kotetsu534 (lol @ the 90/10 split).
It would be interesting to see the breakdown for MMOs. For example I think it's a safe assumption that Eve Online is male dominated whereas the pop culture friendly World of Warcraft has a more balanced split.