Denise Cummins Ph.D.

Good Thinking

It’s Not Just a Woman’s Issue

Male fertility declines rapidly after age 35, too.

Posted Jul 11, 2012

Most people believe that only women have a “biological clock” and that men can safely have children at any age.

Sorry to say, it isn’t true. Here is what you need to know when it comes to deciding whether and when to start a family.

First on the list is that male fertility declines rapidly after age 35, just as in women.

A 2008 study analyzed samples taken from more than 21,000 intrauterine inseminations. They found that sperm from men in their late 30s was less likely to result in healthy pregnancy than sperm from younger men. Men older than 40 were successful in fertility treatment only in 10% of cases, and one third of these cases resulted in miscarriages.

Another study examined the rates of successful pregnancies in 59 fertility clinics for almost 2,000 couples. They found that women younger than 30 years old were 25% less likely to conceive a baby if her male partner was 40 years or older, and that women 35 to 37 years old were 50% less likely to conceive if the male partner was 40 years or older.

Second, older men are more likely to father children with birth defects or other genetically-linked disorders:

A 2006 paper published in the Proceedings of the National Academy of Sciences reported a steady increase in sperm DNA fragmentation with increasing age of the study participants, along with increases in gene mutations. The co-author, Dr. Andrew Wyrobek stated "This study shows that men who wait until they’re older to have children are not only risking difficulties conceiving, they could also be increasing the risk of having children with genetic problems.”

A 2003 study reported in the Journal of Urology found that the incidence of Down Syndrome pregnancy among 35 year-old women with husbands 40 years of age was twice that of 35 year old women with husbands 24 years of age.

• Men over 40 are six times more likely to father an autistic child, according to a 2006 study published in the Archives of General Psychiatry.

• Men of advanced paternal age are also more likely to father a child with schizophrenia, from about 7 out of 1,000 for men aged 25-29 to about 15 out of 1,000 for men aged 45-49.

• According to a 2008 study published in the Journal of the American Medical Association, the offspring of men 55 years and older are almost twice as likely to be diagnosed as having bipolar disorder than the offspring of men aged 20 to 24 years.

Finally, fathers are more than just sperm donors. The amount of time fathers spend with their young children has a pronounced effect of their children’s development. According to a report by the U.S. Department of Health and Human Services: 

• Children whose fathers were involved in their care were 43 percent more likely than other children to achieve high grades in school, and 33 percent less likely than other children to repeat a grade.

• Toddlers with involved fathers are more patient and can handle the stresses and frustrations associated with schooling more readily than children with less involved fathers.

• Infants who have an involved father are more likely to be emotionally secure, and are more confident in exploring their surroundings.

• Sons of involved fathers also have fewer school behavior problems, and girls of involved fathers have higher self-esteem.

All told, it appears that delaying childbearing past age 35 is a little like playing Russian roulette for both men and women. This has profound implications for twentysomethings whose chosen professions (such as law, medicine, or academia) demand that they devote their youth to building careers instead of (as opposed to in addition to) building a family. They run the risk of becoming infertile, having children with genetic abnormalities, or spending insufficient time with their young children to ensure that they will be well-grounded for adulthood.

Dr. Cummins is the author of Good Thinking: Seven Powerful Ideas that Influence the Way We Think (Cambridge University Press), and The Other Side of Psychology: How Experimental Psychologists Find Out about the Way We Think and Act (St. Martin’s Press).