I'm not sure if anybody suspected that rats reacted differently to how men and women smell, but only women were allowed to work as rodent caretakers or be in the rodent room at my school. Our professor showed the guys the room once, but we weren't allowed to talk, since she thought it was men's voices that set the rodents on edge.
In case anybody is wondering what our experiment was, we were measuring whether caffeine affected the VO2 of mice. Their oxygen consumption pegged anytime any of the guys handled them.