~OMG FACT~

All of Santa Claus’s reindeer are technically female.

Reindeer are the only species of deer in which both males and females grow long antlers, however, the sexes shed their respective antlers at different times! The females shed them around May, while males lose their racks during November. This means that male reindeer typically would not be sporting their antlers around Christmas - which leads us to assume that, regardless of their names, NONE of Santa’s reindeer are male!
(source)