If you go by the names, then Vixen would be the female. However, if you look at all of the illustrations of Santa's sleigh-pulling reindeer, they still have their antlers during their Christmas Eve ride. If you were to answer this trivia question according to zoology, then ALL of Santa's reindeer would be female since male reindeer lose their antlers in the November to early December timeframe while female reindeer don't lose their antlers until January!
Vixen- because the meaning of the word Vixen is almost always related to a woman.
Prancer- This is kinda a phony answer (not to say I don't believe in santa) But I sent a letter to Santa asking that and he answered a girl.
Dancer-a girl..isn't it kinda obvious?
As Keith Devine has said ,they are all females, but we should have known, only females could pull a sleigh filled with freight and a fat old man in a red suit all around the world in one night. Here's power to your elbow girls,keep bending it.(mines a rye)
Male reindeer shed their antlers between late Sept-Jan, pictures of Santa and his Reindeer always show them with antlers, therefore I recon that they are All Females.
The female reindeer is the 9th one - Olive, as in "Olive the other reindeer"
Half of them are female. Remember, Santa has Magical Powers and can do things like making reindeer not molt. If he can make them fly and visit everywhere that celebrates Christmas in one night, he can do anything.
According to "The Night Before Christmas," we have these reindeer: Dasher and Dancer -> Dancer's the female. Prancer and Vixen -> Vixen is the female. Comet and Cupid -> Comet is the female. Donder and Blitzen -> This one's tough, but we'll call Blitzen the female.