It took 45 seconds for Josephine to push the unfertilised eggs across to Tom’s empty brood pouch (6). As they entered his reproductive system he fertilised them. The sequence allowed Tom to be certain that each and every baby he would carry would be his own. This certainty of paternity is extremely rare in the animal kingdom, and explains why male seahorses put so much effort into raising their offspring.
Now, think through this logically. Why is that women – in humans – do most of the child care? Because they are certain, in a manner that the men aren’t, about the genetic question, obviously.
Cool, so, now we’ve solved that gender care and thus gender pay gap. We’re done, right?