"Why? First of all, we discovered that men cannot breastfeed. Second, economically, we concluded that I was the primary breadwinner, and ultimately, it didn't make sense for me to be sleep-deprived and yelling at the studio executive the next day. And third, as Maggie points out, my wife enjoys raising the baby MUCH more than I do.
"Of course I love my baby. But there is (from my male POV) a weird and primal connection she has with the baby. At this point, she is clearly just a) better at raising the baby; and b) enjoying it more.
"None of this is to say that I don't enjoy the baby, and I do help out a lot, but the connection between mother and baby is one you don't want to mess with. So, while we planned a certain 21st-century liberal approach to division of labor and child-rearing, we found that primarily biology and secondarily economics quickly brought us back to the 1950s. And oddly, we're both OK with it."
Like I said, sometimes reality just gets so darn big, even Yale graduates sit up and take notice.