For two years, Tom Swanson and his wife tried to conceive a child. They were unsuccessful and sought help from Jon Pryor, a University associate professor of urologic surgery.
As a result, Swanson learned he had inherited a condition in which a portion of his Y chromosome was missing and that was causing the couple’s problems with having a baby.
Swanson participated in a study conducted by Pryor and Ken Roberts, assistant professors of urologic surgery. The recently completed study, which will be published today in the New England Journal of Medicine, discovered a genetic link to infertility for men who are missing part of their Y chromosome.
Fathering a family will prove to be difficult regardless of the man’s sperm count for men who are missing part of the long arm of their Y chromosome, the study said. In addition, if the man manages to father a son through in vitro fertilization, his son is likely to have the same genetic omission.
The discovery could bring relief to half of the 15 percent of couples whom have trouble conceiving. At the same time, however, it raises ethical questions about the possibility of conceiving a son whom would carry on the “microdeletion” of the Y chromosome.
The researchers found that about 7 percent of the infertile men studied had trouble fathering children because part of the Y chromosome is missing. A couple is considered infertile if it has not been using birth control for one year and still cannot conceive.
The percentage might seem low, Pryor said, but the condition is the second leading cause of male infertility ever diagnosed. The foremost cause of infertility in men is a condition called varicocele, where the veins of the scrotum are dilated. About 36 percent of infertile men have the condition, Pryor said.
The study will end much of the trial-and-error attempts to treat a couple’s difficulty in conceiving children, Roberts said. Previously, when a couple sought help for an infertility problem, doctors would have to try a number of therapies, because they didn’t know just what was causing the problem.
Now couples can be tested; if the man is found to have a deletion on the Y chromosome, doctors can suggest in vitro fertilization right away instead of wasting a year trying different therapies, Roberts said.
Swanson and his wife were able to conceive a child through in vitro fertilization using a donor’s sperm. Four months ago, the couple celebrated the arrival of their daughter.
“The thought never really came into my mind that we wouldn’t be able to have a child,” he said. “That’s why we kept trying so hard.”
Swanson said he considered using his own sperm, but it was too expensive. Also, passing on the condition to a son would not be a consideration because now that he understands what the problem is, Swanson said he could let his son know what to do to have a family.
“If my father had known, he could have helped me with our conception,” he said.
In the past, conditions causing infertility often were not passed on because the person could not reproduce, Roberts said. Today, many patients do conceive through in vitro fertilization, passing the problem on. “And if you do have a boy, the chances are approaching 100 percent that he will have the condition,” he said.
Most patients won’t change their plans to father a child in vitro even knowing they could pass the condition on to their sons, Pryor said. “Most say ‘My son will have the same problem. Big deal,'” he said.
Swanson affirmed Pryor’s remarks, saying “It eases my mind knowing what the problem was those last two years. It’s possible my son can have the same condition, but it’s still nice to know.”
The research brings up some difficult issues, said Jeffrey Kahn, director of the University’s Center for Biomedical Ethics. Although men might be knowingly passing on a genetic defect, they are still bringing a person into the world, he said.
Furthermore, the study allows fathers with the Y chromosome deletion to know their sons will have problems conceiving a child in the traditional manner. Kahn said this allows men to educate their sons about having children with the help of medical technology, which might help the next generation with the condition to have children.