Supporters of circumcision have argued that smegma contributes to the development of penile cancer. There is no evidence, however, to support this claim.
More About Smegma
Smegma provides a protective coating for the clitoris and the glans of the penis. In the case of the penis it serves as a source of natural lubrication between the sensitive glans and the foreskin aiding in their movement during sexual intercourse.