Proof that your wife's pregnancy and your new status as dad does indeed mess with your head (in a good way!):
"[Hormone changes related to partner's pregnancy] also change his perceptual  circuitry, increasing his ability to hear a baby cry, something many men  can't do very well before their wives are pregnant.  And a word  to the wise for all the young mothers who are reluctant to let your  husbands hold and care for your newborn. The more hands-on care a father  gives his infant, the more his brain aligns with the role of  fatherhood. So, hand over the baby."
Read the 
whole story here!