Do older dads have an increased risk of fathering children with autism?

Q: I'm 31 and pregnant; my husband is 48. Is it true that older men have an increased risk of fathering autistic children?

A: A recent Israeli study of more than 300,000 young adults showed that autism rates in the offspring of men who were 40 or older when their babies were conceived were almost six times that of the children of fathers 29 or younger. (The study found no link between autism and maternal age.) The researchers are now looking for reasons; there is speculation that sperm-producing cells spontaneously mutate as men age.

Much more study of paternal age is needed if we are to better understand its impact.