Researchers studied nearly 138,000 men over 10 years. Fathers were 17 percent less likely to have died from heart disease than childless men were.
"There is emerging evidence that male infertility is a window into a man's later health," said Dr. Michael Eisenberg, a Stanford University urologist and fertility specialist who led the study. "Maybe it's telling us that something else is involved in their inability to have kids."
There were several caveats, including not having the cholesterol or blood pressure information on the men, which are key heart-risk factors.
Researchers also didn't know how many men were childless by choice and not because of a fertility problem.
The study - by the AARP, the government and several universities - is the largest ever on male fertility and mortality
The study is online in the journal Human Reproduction .
The Associated Press contributed to this report.