"According to the Alaska Department of Fish and Game, while both male and female reindeer grow antlers in the summer each, male reindeer drop their antlers at the beginning of winter, usually late November to mid-December. Female reindeer retain their antler until after they give birth in Spring.
Therefore, according to every historical rendition depicting Santa's reindeer, every single one of them, from Rudolph to Blitzen had to be a female."
Rudolph never seemed really at peace with "himself" on the Christmas special. The red nose is probably from drinking too much because she was hiding the truth of her identity from the world all those years.
And all those other "male" reindeer were obsessed with showing their prowess at the reindeer games. It all makes sense now. The females were trying to fool Santa so they could continue to provide for their families. Santa had so many problems with the elves that he was oblivious to the transgender lifestyle going on amongst the reindeer.