I think he was talking about all the little sperms and eggs that don't get a visit from each other. Not abortion. Mathematical chance at life. If all the sperm made it to a person this would be one full planet.
No, he's talking about the set of possible individuals based on our DNA.
His point is that simply by living, we've beaten the odds. I don't disagree with that, but we shouldn't act like aborted fetuses are nothing more than a bit of tissue, either. They beat the odds and formed a combination that would have resulted in a person, if it had been left alone.
I'm not saying that's an excuse to try to ban abortion, but we shouldn't pretend that it doesn't matter.