(Sorry in advance for my long answer!) The estimate is that 2% of both sexes are some type of asexual. Where the huge gender difference happens isn't relevant to asexuality. Men on average have a much higher libido than women. It's important to note that there is zero connection between asexuality and libido. Asexuality is an absence of sexual attraction for a partner, while libido is a general impulse to have sex, that isn't connected to a partner. While this may be confusing, there are some asexuals who have a very high libido, since libido and asexuality are separate. In that case, they love to have sex, but seeing a potential partner has absolutely no effect on them, it's just that they "feel the urge", without a nearby person ever being the cause. For them, a "sexual fantasy" about a certain person doesn't exist (but a generic urge for having a particular intimate activity could exist, just not tied to who it would be with). Another d...