Toxic Future Fathers
Birth defects, childhood cancer, and miscarriages have all been linked to the health of a father's sperm. Here's what dads-to-be need to know about the role they play in their unborn children's health
The Taboo Question
A 29-year-old Boston woman (some identifying characteristics and information about this couple have been changed) couldn't understand why she had suffered two miscarriages. Her gynecologist had run a battery of tests and found nothing wrong with her. That's when she began to consider a question women rarely ask: Is it possible my husband can't have healthy children?
Her husband, 40, didn't want to come to the office of Marc Goldstein, M.D., professor of urology and the director of the Center for Male Reproductive Medicine and Microsurgery at the New York Hospital-Cornell Medical Center, and was angry when they arrived. And when Dr. Goldstein offered a possible solution to the mystery of her miscarriages, he says, "she was angry at her husband and he was angry at me."
The husband was a construction worker and routinely involved in the demolition of old buildings that had lead pipe or lead-based paint. "That was a possible clue," says Dr. Goldstein. A man's exposure to lead has been associated with his partner's miscarriages
. "He was also a heavy drinker -- a six-pack every night," Dr. Goldstein says. Clue two: Animal studies raise questions, still largely unanswered in humans, about the longest and most painful kind of hangover: damage to the fetus caused by a father-to-be's excessive alcohol consumption. And the man had smoked two packs a day for 25 years, since he was 15, a third hint of danger. Recent studies with human subjects suggest that male smoking can harm sperm, causing miscarriage and passing on a slight but significant legacy of cancer to offspring, even if the mother doesn't smoke.
But what evidence was there that the man's bad health habits had caused these particular pregnancy failures? It was circumstantial but compelling, and "something he had never told his wife before," Dr. Goldstein says. "His previous wife had miscarried twice." If there was something wrong with her, the problem seemed to disappear after their divorce. "When his first wife got married again," Dr. Goldstein says, "she went on to have healthy children with her next husband."
Miscarriages happen to at least one of every five pregnant women. In some cases, these "spontaneous abortions" are nature's way of ending a pregnancy likely to lead to a baby born with serious malformations. They can also be a sign that the mother's womb is inhospitable to fetal growth. In the case of the Boston woman, doctors had already ruled out typical causes. So Dr. Goldstein narrowed in on how her husband might have triggered the pregnancy problems.
Tests of the man's blood revealed lead levels within a normal range, so that didn't appear to be the culprit. But when the man's sperm were examined under a microscope, they were clearly misshapen. Some had two tails. Some had irregularly shaped heads. Research shows that smoking and drinking alcohol both can distort sperm's form. And abnormally shaped sperm is associated with a higher than average incidence of miscarriage.
Drugs and alcohol aren't the only cause of abnormal sperm shapes. Varicocele, for example, a painless swelling in the scrotum from varicose (enlarged) veins, can lead to a distinctive narrowing of the sperm. In itself, varicocele isn't a serious disorder. But it can contribute to infertility and, experts say, the narrowing can be associated in some cases with miscarriage -- most likely if the man uses drugs or smokes cigarettes. That means a man with varicocele who drinks to excess or smokes increases the risk of disrupting his wife's pregnancy.
"It's true that misshapen sperm are less likely to succeed in fertilizing an egg," Dr. Goldstein acknowledges. "But if they do, the fetus is more likely to have problems and the odds of miscarriage go up." His prescription to his alcoholic and cigarette-puffing patient was a strong suggestion that he join Alcoholics Anonymous to help curtail his drinking and buy a nicotine patch to assist in weaning him of his cigarette addiction.
"He quit smoking and got into AA," Dr. Goldstein says. Six months later, the couple hadn't yet conceived. But the shape of the sperm had significantly improved -- they had a classic bulbous head and long, thin tail -- increasing the odds that his better health might spawn a successful pregnancy. And eventually it did: A few months after that, the woman became pregnant, and last May the couple became the proud parents of a healthy baby.
"All the eggs a woman will ever have are created when she is a fetus inside her mother," says Bruce Ames, Ph.D., professor of biochemistry and molecular biology at the University of California, Berkeley. Sperm cells, by contrast, are produced continuously through cell division all during a man's adult life. At every cell division, the sperm are at risk of mutation -- a small change that can mean a big problem for the man's children. That's why, Ames argues, "fathers ultimately contribute more to the risk of gene mutations than mothers."
So where does that leave a concerned dad-to-be? Doctors suggest three strategies for producing safer and healthier sperm: