Dear old dad

A recent Stanford study shows that the percentage of newborns in the United States whose fathers are older than 40 nearly doubled between 1972 and 2015, a trend with both positive and negative implications.

Older dads likely will be more involved in child-rearing, and have higher levels of education, better jobs and more resources.

But genetic mutations in sperm as men age mean there are “associations between older fatherhood and higher rates of autism, schizophrenia, chromosomal abnormalities, some pediatric cancers and certain rare genetic conditions,” says Michael Eisenberg, MD, assistant professor of urology and senior author of the study, published online Aug. 30 in Human Reproduction.

Eisenberg also notes a steady increase of the average age of U.S. dads of newborns from 27.4 years old to 30.9.