Help me solve the following riddle please...?

In the movie Extract, and industrial accident occurs when a projectile hits a man in the groin. The injured worker is taken to a hospital where one testicle has to be removed immediately. ume that this fact of removal is UNKNOWN; all you know is that he was taken to the hospital with a groin injury. Then, given that this man has at least one testicle when released from the hospital, what is the probability that he has two testicles (attached to his body) when released from the hospital?