Compared with a control group, Baker found that men with testicular cancer were less likely to have fathered a child and had significantly fewer offspring than the healthy men. When narrowed to include only men who had intentionally tried to father a child, the results were similar. The most common problem associated with testicular cancer is a condition known as cryptorchidism - this is when the testicles of an infant haven't descended into the scrotal sac at birth. But even though this is a problem that may predispose a male to this disease, only 10 percent of men with testicular cancer had this condition at birth. Baker says that based on their study results, it would appear that many of these men had been ill all along.
Some experts think that more data is needed.
Determining fertility can be difficult, Baker says, because a man would be unaware that he was having fertility problems unless he was actively trying to father a child. Fertility is measured on a continuum, and unless they've ever tried, they wouldn't know they were infertile. It's only later then, if they want to get married and have children, they find they have a problem.