How is that possible for the King to have so many kids?

I remember there was a scene where King Mongkut had answered Sir John Hay's how many children do you have question and King Mongkut answers " I have only 106 I was not married very long, next month we're expecting five more.". I was thinking how can a man and meaning one man can have 100 and something kids in a short period of time? I know he has many wives and concubines but it seems like he doesn't have time to conceive so many children and it seems like an impossible task to achieve, not even the Mormons have that many children. So is it that possible for the King Mongkut to sire so many children in such a short period of time? The movie made the reason why King Mongkut had so many children because either he had children before he royal reign or he had sexual intercourse with every wife or concubine he had everyday.