Q: The research now shows that men, once presumed to be fertile well into their 60s or beyond, have a biological clock ticking. What are the effects of aging on a man’s fertility?
A: What is a biological clock? For women we know it means a decline in fertility, a decline in hormones, primarily estrogen, and an increased chance of having genetic abnormalities. That’s exactly what happens to men. Exactly, except it was never really appreciated. As men get older, there’s a decline in fertility, a decline in testosterone, and the sperm from older men are associated with more genetic abnormalities in babies born from that sperm.
Q: Why wasn’t it appreciated before?
A: In the past, when we were talking about the biological clock for men, we were talking about rare disorders associated with older men, such as dwarfism and some other rare diseases that caused the baby to die very early. So nobody paid attention. Recently, in the past four or five years, the data has come out that Down syndrome is associated with an older father. Then studies showed that schizophrenia was associated with advanced paternal age and, more recently, that autism-related disorders were associated with older fathers.
Q: Can you talk about the evidence regarding these diseases?
A: For men over 40, there’s almost a six-fold increase in autism disorders in their children compared with men under 25. That’s significant. With schizophrenia, for men in their 50s, there’s a three-fold increase compared with men under 20. And there’s a direct increase associated with age. The older the man, the higher the risk of schizophrenia in his offspring.
Q: At what age do the risks begin to rise?
A: When both the man and woman are over 35, you have a synergistic effect of their age. For example, with Down syndrome, as long as the woman was under 35, it didn’t matter how old the father was. However, if the woman was over 35, there was a dramatic age effect from the father. With autism and schizophrenia, the age of the mother was not protective.
Q: Are there other diseases associated with advanced paternal age?
A: We don’t know what the impact of male age is. We have just scratched the surface. With women we talk about chromosomal abnormalities and the diseases attributed to having, for example, one too many chromosomes. In men, we talk about gene mutations. When you’re talking gene mutations, who knows how many diseases can be associated with it? The more we look, the more we find.
Q: Do we know how a man’s age affects his fertility?
A: People assume that older men are still fertile since they can produce sperm. Theoretically you can have children at any age if you have sperm. But is that sperm going to give you the same genetic qualities as the sperm from a younger individual? We know that fertility does decline. We know that after the age of 30, there is a drop in testosterone of 1 percent a year. Testosterone is the energy, the hormone that you need to make good-quality sperm. It takes much longer for an older man to have children. But we haven’t studied fertility of men in their 60s or older.
Q: What does age do to sperm?
A: Cells in the body deteriorate as they get older. Sperm cells constantly regenerate themselves, as opposed to eggs. But the constant turnover of sperm cells lends itself to genetic mutation. The older you are, the more sperm cells have divided and the more divisions, the more chance for a disorder to occur.
Q: Is the big issue a decline in sperm count?
A: We know there is a decline in sperm production as you get older, but what we see dramatically is a drop in semen volume, the sperm movement and changes in the shape of the sperm. There are many more abnormal shapes as men get older.
Q: What age does the male clock start ticking?
A: Over age 30, there’s a decline in men’s health, at least hormonally. Since we know that’s associated with sperm production and possibly genetic abnormalities, that’s when it starts, but it’s gradual. If a couple is both over the age of 35, there should be increased awareness that genetic testing is needed.
Q: What can older men do?
A: If you are over 35, you should do everything you can to decrease your likelihood of having abnormal sperm or genetic abnormalities. That means leading a better lifestyle, quitting smoking, taking care of infections you might have, and taking care of varicoceles — enlarged veins in the scrotum that could harm sperm production. We’re trying to reverse the biological clock by improving sperm production. A healthy lifestyle can help you delay these age factors that can lower fertility.
Q: Which lifestyle factors age sperm?
A: I always say that having a baby is like running a marathon. You have to be in the best shape possible to run a marathon and to have a baby. You need to avoid any toxins in the body. Avoid medications if you don’t need them, avoid anabolic steroids, avoid alcohol and cigarette smoking for sure. Have a very good low-fat diet, and exercise to increase your testosterone level.
Q: Is the obesity epidemic affecting male fertility?
A: Men with a body mass index of over 25 have a 20 percent increased chance of infertility. There’s a direct correlation between waist size and testosterone levels. The bigger the waist, the lower the testosterone. Being too thin is also bad; it has been shown that if you’re too thin, having a B.M.I. of less than 20, you have a lower sperm count. B.M.I. should be between 20 and 25.
Q: Is there evidence that a healthy diet improves fertility?
A: I always say that the penis is the dipstick of the body’s health. If a couple is having a problem having sex, there is a problem to either the hormones or the blood vessels there. We know that if you have a high cholesterol level, that’s a risk factor for erectile dysfunction, and therefore fertility function.
Q: Are there any other risks to a man’s fertility?
A: Avoid Jacuzzis, which can heat up the testicles and lower fertility. Environmental toxins, like heavy metals, are known to cause a problem with male fertility. Lead, cadmium (which you get from cigarette smoking) and excessive mercury (from too much exposure to certain fish) have been shown to decrease sperm function and counts.
Q: What is your overall recommendation to men?
A: The biggest problem is that couples are waiting longer to have children. Young people need to be aware of this information. If my children would ask me, “Should I wait until I’m over 35 to have children?” I would say, “No, have children earlier rather than later.”
Publish date: 5/2/2008