Psychology, which I'm sure you know covers the endocrine system and how hormones affect our behaviour.
ETA: Hud the bus, you didn't answer my question; do these side effects that you refer to only affect women of an older vintage?
Like I've said, I don't know anyone with the rod to complain of any side effects, but that may be the fact that those who I know that have the rod are in their early 20s.