I haven't heard or seen what his mother said, but she may have laughed, that someone was actually suggesting that his 19 year old son (who might not be in a steady, strong relationship) would start making kids, when he is at the high
of his career.
Many times people can't actually help how they are. It is in their nature. And to "butch up" just to get away from gay rumors sounds actually awful. Changing yourself to please others is just a depressing thought.
Don't quote me word for word, but his mother said: "Grandkids from Tom? Hahahaha!"
There is a train of thought that 'campness' in the gay community is something you develop to fit in with your peers.