In cases of infertility, the spotlight always used to be more focused on the woman’s reproductive system, with an emphasis on her age and egg quality. But there is growing recognition that men also have a ticking biological clock.
Hollywood seems to be overflowing with older dads – like actor Alec Baldwin who fathered a child at age 63 – and that gives a false impression. The truth is, fertility decline might be more subtle for men than it is for women, but it does happen. As men grow older, their sperm is more susceptible to DNA damage which can mean it takes longer for their partner to get pregnant and increases the risk of a miscarriage. One study from Monash University showed that a man’s age has a negative effect on fertility, even if men partner with younger women. The chance of conceiving halved if men were over 50, compared with those under 40.
The message is that men also need to think about how big a family they want and the time frame they have to complete it, says fertility expert Dr Devashana Gupta, the medical director of Auckland clinic Repromed.
Men do have an advantage in that they can boost the quality of their sperm to a certain extent. While women are born with a supply of eggs and are unable to make more, men regenerate their sperm every three months or so.
“So, if they’ve been living an unhealthy lifestyle, they can remedy that in the next cycle,” says Gupta.
Many aspects of lifestyle have an impact on sperm. Heat is a major factor. Gupta recalls treating one man who enjoyed daily hot spas and had poor-quality sperm as a result. After three months without sitting in the spa, he repeated the semen-analysis test and his sample was normal.
“The scrotum and testicles hang outside the body because sperm like to be a few degrees cooler than the core body temperature,” explains Gupta. “If men wear tight underwear, or cycle a lot wearing Lycra or take spas, it raises the testicle temperature. Also, when men are obese and have a lot of fat around their thighs and abdomen, that increases heat as well and can affect the sperm.”
Smoking and vaping reduce sperm quality, count and motility (ability to move). And so, to qualify for funded fertility treatment in New Zealand, both men and women need to have abstained for three months. The other familiar health advice also applies – stay active, eat well, manage stress, cut down on caffeine and alcohol.
Long-term use of painkillers and other medications can affect sperm health, as can exposure to some chemicals. And men who are taking testosterone need to stop while trying to procreate as it is effectively a male contraceptive.
Evidence is limited but one small study, published in ACS Omega in March last year, suggests Covid-19 infection can reduce male fertility. In a study at the Indian Institute of Technology, researchers examined semen samples from 10 healthy men and 17 who had recently recovered from Covid. The recovered men had significantly reduced sperm count and motility, and fewer normal-shaped sperm, than those who hadn’t been sick.
Gupta says this could be due to the high fever. But there may also be immunological reasons. “There’s no evidence that it causes long-term sub-fertility,” she adds. “But increasingly, we’ve had young men come who want to freeze sperm in case they get Covid. I guess it’s good that they are thinking about their future fertility.”
It takes about eight to 10 weeks for sperm to develop in the testicles and then it is stored in a coiled duct behind the testes, called the epididymis, where it finishes maturing.
“If it sits there for too long then it loses its motility,” explains Gupta. “So, when we’re doing a semen analysis, we say no more than three days’ abstinence [from sex] to get the optimum sample. Studies show that frequent ejaculation is more helpful for fertility. There’s never too much; the more ejaculation you can have, the better.”
