Autism and schizophrenia linked to father's age (Updated)

UPDATE: New study suggests children of fathers over 45 are at increased risk for autism, ADHD and other mental health issues, Globe & Mail reports. See also "Kids of Older Parents," interview at CBC.ca. (March 2014)

UPDATE: Maclean's Magazine offers commentary on this study and more recent info in their article "The dangers of older dads" (February 2013). See also Babble.com's recent article How Old Is Too Old.

A study of paternal age published this week (in the online journal Nature) has found further evidence that men have a ticking biological clock, too: Older men are more likely to father children who develop autism and schizophrenia.

If you're a guy who wants to wait to have kids ("I just don't see what the big rush is!"), take a look at this new research, which suggests that the risk of these disorders increases by two percent for children fathered by dads over 40.

The findings may partially explain why more kids are being diagnosed with autism these days. The increasing average age of dads “could account for as many as 20 to 30 percent of [autism] cases,” says The New York Times. (The researchers focused on 78 Icelandic couples who had no signs of a mental disorder, but whose children developed autism or schizophrenia.)

And all you ladies out there are off the hook: "The age of mothers had no bearing on the risk for these disorders, the study found."

For more, check out this article in The New York Times.

This study calls into question what we see in the media — specifically Hollywood parents reproducing (seemingly miraculously!) later and later in life. Check out our celeb gallery featuring some of these older dads.

Here are seven facts about paternal age and how it could affect your offspring:

1. Since 1980, the birthrate of fathers who are 40 and older has increased by more than 30 percent.

2. Meanwhile, one in 88 eight-year-olds has been diagnosed with autism — a tenfold increase.

3. The risk of chromosomal abnormalities like Down’s Syndrome increases with a mother’s age. But more complex developmental problems, including psychiatric issues, usually originate from genetic material in the father’s sperm, not the mother’s egg.

4. Children born to a 20-year-old father have, on average, about 25 mutations that can be traced to the dad.

5.  Children born to a 40-year-old father have, on average, about 65 mutations that can be traced to the dad. This works out to be about two more mutations with each passing year. (However, remember that many mutations are harmless.)

6. Fifteen mutations, on average, come from the mom’s side, no matter her age. (This is because egg cells are considered fairly stable compared to sperm cells, which divide every 15 days. Continuous cell copying is what leads to random glitches in our DNA.)

7. A 94-year-old village elder in rural India claims to be the world’s oldest father.

Originally published August 2012.

What do you think about this latest study? Will it impact your family planning?