Contrary to the popular belief, experts warn that fertility does decline in men as they age, though not as dramatically as it does for women — and for different reasons.
A reproductive endocrinologist, Dr. Jane L. Frederick, says men over the age of 40 are 30% less likely to impregnate a woman, compared to younger men under the age of 30.
Data also showed that it took older men longer to get their partner pregnant — a five times increase compared with men under 25.
Male fertility is an under-researched field, yet there are some findings to suggest male biological clocks do have a significant impact on the likelihood of a successful pregnancy.
A 2017 study from Beth Israel Deaconess Medical Center and Harvard Medical School, for example, found that the chance of live birth decreased with older men, even if their partners were younger women.
While men often can have biological children much older than women can, their fertility is still impacted by age.
Age impacts the health of one’s sperm, says Dr. T. Mike Hsieh, the director of UCSD Men’s Health Center and professor of urology, who notes that “increased paternal age is associated with a decline in sperm count, sperm quality, semen volume, testosterone and ability for sexual activity or erectile dysfunction.”
But one reason for this decline may have to do with how healthy an individual is as a whole, explains Dr. Paul Turek, a urologist and expert on fertility in men.
The older a man is, the more likely he is to be exposed to certain environmental factors or develop health conditions that impact fertility by affecting the DNA package of his sperm.
“Eggs try as hard as they can to ‘fix’ the DNA early on after fertilization, but if the load of damage is in excess of the egg’s capacity to repair it, then there will be no pregnancy or possibly a miscarriage,” he says.
