even balancing those, there were a few types of monsters that skewed towards more males than females. on the other hand there were quite a few monster types that skewed female (as in, there were at least less than half as many male monsters of that type than female)

so i get that the monster matching is not based on gender, and that it just so happens that a bunch of female characters were brought in with traits that fit better for harpy and a bunch of male characters were brought in with traits that fit better with werewolves. i still find that interesting!