I recently saw a 50-year-old man and his 35-year-old wife in clinic who have been trying to get pregnant for the past 18 months. The couple told me that conceiving their daughter, who is now 7 years old, was a piece of cake, and within a couple of weeks of trying they were pregnant. But that was then. Now, their efforts at a second child had been fruitless for well over a year and they needed help.
Had this couple faced conception difficulties even a few decades ago, the blame for their infertility would have fallen squarely on the woman. But modern science now definitively tells us that the male partner is responsible in up to 50% of cases of couple infertility.
Furthermore, in this case the mother had just hit the magic age of 35, and now carried the stamp of “advanced maternal age,” making her less likely to conceive.
But what about dad? Is he of “advanced paternal age”? He’s 50, after all, and studies over the past two decades tell us that paternal age is something we need to think about, both as physicians and as men, because the “male biological clock” is indeed ticking. For this couple, dad certainly could be causing, or at least contributing to, the conception difficulties just by virtue of his age.
So, what’s some of the evidence for a male biological clock and how should this change how men approach their lives and their interactions with health care?
We’ve known for a long time that a man’s testosterone, often considered the hormone of male vitality and youth, declines progressively starting in his 30s. Low testosterone levels are associated with increased cardiovascular risk and mortality, and changes in bad cholesterol.
Low testosterone levels can also decrease sex drive, worsen erectile function, and affect fertility, and men with higher testosterone levels have lower risk for some of the above conditions than their counterparts with lower testosterone levels.
From the standpoint of fertility, older men are less likely to conceive a child, take up to five times longer to conceive, are more likely to initiate a pregnancy that results in a miscarriage or stillbirth, and are more likely to have a child with a neurological or behavioral disorder.
Older men also have more mutations in their genetic code than women of the same age or younger men, and these can be passed on to their offspring. Men who are older have fewer sperm and their sperm quality is lower than that of younger men — more of their sperm have damaged DNA, which can decrease their ability to initiate a pregnancy.
More recent research has shown that infertile men are at increased risk for cancer and other medical conditions, including cardiovascular disease, endocrine, genitourinary and skin diseases. More generally, infertile men, regardless of age, are more likely to have low testosterone levels as well. Thus, a man’s fertility status, particularly if detected early in life, can be a marker of his general health.
While we are learning about men’s health more rapidly now, research on men is significantly behind — a decade or more — similar research in women, and there are far fewer urologists than gynecologists who can counsel male patients and educate the public and other physicians.
In the case of the 50-year old father, he didn’t come to see me seeking advice about “advanced paternal age.” He came because he wanted to have another child with his wife. His wife knew that she might be less fertile because she was 35, but neither had heard that the same might be true for him.
Without broader public and physician knowledge of the relationship between male age, fertility, hormonal status and disease, men will continue to avoid doctor visits. As it stands, men are 80% less likely than women to go to the doctor. This may be related to a lack of emphasis on preventive care in men, in contrast to women, who are advised to have regular gynecological visits starting in their teens.
Because of our growing knowledge about the relationship between male age and disease markers that can become apparent early in life, physicians have a responsibility to inform the public. Physicians treating couples for infertility should encourage male partners to be evaluated by a urologist, and young men with fertility or hormone-related issues should be checked out.
We should all become aware of the risks of male aging beyond common conditions, such as hypertension, diabetes and heart disease. Having children is very meaningful for many men, and looking forward to a long and healthy life will allow them enjoy fatherhood.