When a bunch of women are around each other for a while, their periods will begin to happen at the same time, which is just really weird. Men don't have anything like that. The closest we have is that when in a room full of just guys, if one of us farts, sometimes each of us tries to fart. But it's not like our colons communicate with each other via hormones and synch up or something.
[Who says these have to be deep?]