Women.
A bit of info....When a baby is first conceived, they start off as a girl (yes, all you boys out there...at one point you were a CHICK). Then Evil comes by (that's the Y-chromsome) to try and change the baby into a boy. Only the tough ones survive and fends off that nasty Y-chromosome.
Pretty. Hyper.
Got a library. Many are overdue!
Hercules!