Study Says Male Fertility Falls After 35

Human fertility starts to decline earlier than previously believed, new research suggests, providing the most precise insight yet into when biological clocks start ticking loudly ? at age 27 for women and 35 for men.

Until now, it was thought that women's fertility starts to drop significantly in the early 30s, with a big plunge after 35. But the new study indicates that, on average, female fertility begins its meaningful slide at age 27.

And while the decline in human fertility tied to aging had traditionally been attributed to the female factor, the study, published Tuesday in the journal Human Reproduction, showed that men's fertility starts dwindling after 35.

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A recent report from the Journal of the American Medical Association looks at past research to examine why aging men experience declining fertility.

It appears that men older than 35 are twice as likely to be infertile as men younger than 25.


As men age, both the number and quality of their sperm decline — so older men become less likely to father a child and more likely to father a child with schizophrenia, Down syndrome, or other problems.

A recent study suggests that autism, an increasing problem with no known cause, may also be linked to paternal age because men 40 years or older are almost six times more likely to have a child with an autism disorder than men younger than 30.

Miscarriages also are more common as dad gets older.


It's not unusual for a woman to get her hormones, ovulatory function and fallopian tubes tested months before her husband has even had a basic semen analysis.

Given that 20 percent of couples are infertile because of abnormal or absent sperm and that 27 percent of infertile couples have a combination of male and female factors, it makes sense to evaluate a man's equipment, so to speak, sooner rather than later.