Is the average woman capable of having 19 children?

I am not saying it is impossible because people have done it real life. However, the question is if the average woman could do it. My answer is still no because 19 births is so far out on the distribution curve. The real average is probably closer to what you see in agricultural societies that need(ed) as many helping hands as they can get. That number is in the high single digit range.

My grandfather has the highest number of siblings that I am personally familiar with. He is one of 12 and that is only because his father was a fire-and-brimstone preacher that believed his job was to populate the Earth with other Christians of his type. They were on a mission from God and 12 was the best they could offer. Even then, some of the kids died extremely young.