Men have biological clocks, too?

When I was pregnant with my youngest child, I recall my doctor mentioned my “advanced age” several times. A bit aggravated, I planned to assure her that I was aware of my “advanced age” — 37 — so she didn’t need to keep bringing it up, but she didn’t bring it up again (maybe I gave her the evil eye).

alarm clockNow a study led by Brian D’Onofrio, an associate professor in the Department of Psychological and Brain Sciences at IU Bloomington, is drawing more attention to men’ biological clocks.

Read the news release

CNN’s Sanjay Gupta discusses ‘the clock’ in a video

Examining an immense data set — everyone born in Sweden from 1973 until 2001 — the researchers documented a compelling association between advancing paternal age at childbearing and numerous psychiatric disorders and educational problems.

Among the findings: When compared to a child born to a 24-year-old father, a child born to a 45-year-old father is 3.5 times more likely to have autism, 13 times more likely to have ADHD, two times more likely to have a psychotic disorder, 25 times more likely to have bipolar disorder and 2.5 times more likely to have suicidal behavior or a substance abuse problem.

“We were shocked by the findings,” D’Onofrio said. “The specific associations with paternal age were much, much larger than in previous studies.

He told reporters with the New York Times, TIME and other outlets, that the findings surprised him and his collaborators at Karolinska Institute in Stockholm so much that they put the data through a statistical ringer, controlling for various factors.

“We spent months trying to make the findings go away, looking at the mother’s age, at psychiatric history, doing sub-analyses,” D’Onofrio told the New York Times. “They wouldn’t go away.”

The study is exhaustive — involving more than 2 million children — and received high marks for its design and ambition. D’Onofrio and other scientists suspect sperm is vulnerable to mutation because it is produced throughout a man’s life.

Some experts point out that the baseline rates for the conditions studied are very low to begin with, so they remain low even when older parental age is considered. D’Onofrio told National Public Radio that men and women who are not ready to have children in their 20s should not stress out. Being older parents has its perks, too.

“Delaying childbearing [also] enables people to become more financially secure, complete more education,” he says. “And that has a positive effect on children.”

Avraham Reichenberg, a professor of psychiatry at the Mount Sinai School of Medicine in New York, wasn’t involved in D’Onofrio’s study but researches similar issues. He also spoke with NPR about the study. It’s routine for doctors to remind women older than 35 that there are risks associated with older motherhood, he said.

“So should be the case, maybe, for fathers.”

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