A nonretractable foreskin is normal up to about age three and should never be forced back. Phimosis in older males can cause urine blockage with acute hypertensive kidney damage. Painful zipper injuries are fairly common in uncircumcised males. Of the 60,000 cases of penile cancer reported since the 1930's, fewer than 10 occurred in circumcised men. Prostate cancer may be increased for uncircumcised men.
Cervical cancer is increased in the partners of uncircumcised men.
Every study ever done has shown increased incidence of urinary tract infection in uncircumcised males. One in 25-100 uncircumcised males will get at least one urinary tract infection. These infections can cause scarring of the kidney and ultimately hypertension or kidney failure. Sexually transmitted diseases are more common in uncircumcised men. Penile hygeine is said to protect against the complications of the uncircumcised state.