When a woman gives birth to a child, the child needs to be able to digest the mother's milk; but when this child is old enough to begin to eat other foods, there is some switching off of this ability to consume milk.
“Flying back from New York, the flight attendant said 'God, I wished you were here yesterday, we had a stroke on the plane. I said, if I have a stroke on a plane, I hope the pretend doctor isn't the one on the plane. I want a real doctor.”