@hideki That's weird. In any country that I know of, women would play boys unless the characters were very, very young (and then real boys would do the job. Think of Takahata's Only yesterday) or they were old enough to use real men their age to do the job. (And by “real men” I mean men who have undergone VA training.)
@josemanuel they use wahmen only when they're very young (like around 10yo or so), but from around 14 years they start using men.