Final answer:
The failure of the urethral valves can cause changes in the appearance of the urethra, such as dilation and enlargement in both males and females.
Step-by-step explanation:
The failure of the urethral valves can lead to changes in the appearance of the urethra. In males, the urethral valves are responsible for preventing the backflow of urine into the bladder. If these valves fail, urine can reflux back into the urethra, causing the urethra to appear dilated and enlarged. This condition is known as urethral valve obstruction. The urethra may also appear tortuous or twisted.
In females, the urethral valves are not as well-defined as in males. However, if there is a failure of the urethral valves in females, it can still lead to similar symptoms such as urinary reflux and dilation of the urethra.