The urethra is the tube that conducts the flow of urine in both sexes from the interior of the body to the external world. In males, semen also travels through the urethra during sexual intercourse. The urethra connects the bladder, the collection site for urine to the outside world. In males, the urethra is 8 inches long, while in females, the urethra is only 2 inches long. So the primary difference is one of length. Another difference would be the path the urine takes getting from the bladder to the external world. In females, the path is more direct, while in males, the path is more curving. This curved path makes catheterization of males more difficult than females. Due to the short length of the urethra in females, infection can be a problem. Urethritis is an inflammation of the urethra common in females. The passing of kidney stones is another affliction that strikes both sexes in the area of the urethra.