We'll never know.
One of the VERY few things that Mao said that I agree with, "Every human is born with two hands and a brain"
You're right .. we'll never know .. but if we just look at American history .. we can presume that a certain percentage of that 40 million would have been exceptional in their life. Maybe some of them would end up being great in education, music, art, or any of the sciences. Maybe one of them was a future President.
And .. while the dems are cheating by every hook or crook, if they hadn't signed on to abortion .. THEY MIGHT HAVE 40 MILLION MORE DEMOCRATS. They have killed their own inheritance. They have diminished themselves by their own hand.