He has one sibling: his older sister, Amy Stiller. Interestingly, Amy Stiller is married to Roger Bumpass, the voice of Squidward on the television show Spongebob Squarepants.
He has a brother.
Ben has a younger sister, Carlee, who plays basketball at The University of Oklahoma.
Yes, his sister, Rachel.
He was a scientist, politician, and writer. There is no evidence that he had kids.