Society is changing. It used to be that as soon as a man and woman got out of high school, parents began pressuring them to settle down, get married, and to start pumping out kids. It was expected that a woman’s “job” was to find a husband to support her and her potential offspring. She then had to make a couple of kids as quickly as possible.
We tend to think of this as an incredibly old-fashioned idea. But there was an actual evolutionary reason for this. Younger fathers and mothers meant fresher eggs and sperm. The longer a person waits to have a child, the more worn out the systems which create the eggs and sperm. It’s more and more likely that mutations will be introduced in that egg / sperm-creating process.
Those introduced mutations are called de novo mutations. The mutations do NOT exist in the father nor the mother. They are wholly new to this sperm or egg. That one-off mutation then impacts how the baby’s “made” from that mutated recipe. It impacts the baby’s entire development, the DNA in every cell of their body, and then any children that baby has.
Study after study find that the older the father, the higher the risk of mutations which cause issues for mental illness, including seizures, schizophrenia, bipolar, and autism.
I made this chart myself based on data from the CDC and US Government.
The mean age of when a father has a child is absolutely climbing. And keep in mind these are the *mean* (average) ages – half of the fathers are OLDER than this! We see all sorts of news reports about fifty-year-old fathers and sixty-year-old fathers. Imagine how many mutations are involved there.
So, absolutely, more men are having babies when they’re older nowadays, in our era of Viagra and “proving your manhood”. That means far more children are being born with a flurry of de novo mutations in their bodies. Some mutations create minor effects that might not even be noticed.
Some create autism.