The hormone progesterone serves vital functions in women who are becoming mothers. It helps keep pregnancies healthy, and it primes pregnant women to show maternal behavior at birth.
That's been known for a long time. What hasn't been clear is the role of progesterone in men--in particular, how it affects their paternal behavior.
It's considered bad form to knock out progesterone in men to see what happens (or to shoot 'em up with it). But Teresa Horton of Northwestern University has done those experiments with male mice.
Sh....