I never really thought about it... but I wouldn't think they were all male... if you go by the names... Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitxen... I'd think at least Vixen would be female. And magic reindeer probably don't have the same social hangups as humans do, but I don't think Prancer is a particularly masculine name. :)