What should men do? Currently, there are no established guidelines on how to perform the vasectomy procedure or follow-up. Williams recommends men get their sperm sample checked at least twice.
"Most of the male fertility specialists around the country recommend checking two semen samples after three months separated by at least one month," Williams said. "Only about two-thirds of men return to the office to have their semen sample checked."
Doctors also say that men should be checked periodically -- something Emmons didn't do -- and most men don't.
"Follow-up examination for 12 months after your procedure to ensure that there are no new or residual sperm. Doctors highly recommend this follow-up check, yet one study revealed that only 3 percent actually took their advice," Williams said.
For men worried about vasectomy failure, Williams recommends checking semen samples at regular intervals to ensure that the tubes remain closed.