That seems a bit strange for a doctor to say that with the removal of one testicle you wont be able to have kids. Unless he is saying this becuase the the alterations to your lymph system or if during surgery a vasectomy was required. I can tell you for a fact that a man can still have children with just one testicle. My father survived testicular Cancer and lost a testicle, yet I am here and I also have a little sister.