In Frank Herbert's Dune universe, do mentats ever have children? As being a mentat is something that can be taught then, I assume, there is no genetic disposition to being a mentat so no great need for them to breed to continue producing the next generation. I haven't read God Emperor of Dune yet so sorry if my assumptions are wrong and these points get covered in the following books.
In Heretics of Dune, Miles Teg (who is also heavily implied to be an Atreides descendant) is written as having been married and had grown children at the time of the story. He is the child of a Bene Gesserit, having been sent for Mentat training at an early age, and later was their Supreme Bashar (General of their armed forces). So I would say that Herbert demonstrated in his writing that nothing about Mentat training precluded marriage or children.