**Core Concept**
Epispadias is a rare congenital anomaly where the urethral opening is located on the dorsal (upper) side of the penis in males or the dorsal aspect of the clitoris in females. It is often associated with other genitourinary anomalies, such as bladder exstrophy. The condition arises during embryonic development, specifically between the 6th and 8th weeks, when the urethral folds fail to fuse.

**Why the Correct Answer is Right**
Epispadias is closely linked to hypospadias, another congenital urethral anomaly where the urethral opening is located on the underside of the penis. Both conditions involve an abnormal development of the urethral folds, but with epispadias, the urethral opening is shifted to the dorsal side. The association between epispadias and hypospadias is thought to be due to a common underlying genetic or environmental factor affecting urethral fold development. In some cases, individuals with epispadias may also have hypospadias, and vice versa.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because epispadias is not simply a mirror image of hypospadias, as it involves a different underlying mechanism and anatomical structure.
**Option B:** This option is incorrect because epispadias is not a normal variant of male genitalia, but rather a congenital anomaly that requires surgical correction.
**Option C:** This option is incorrect because epispadias is not a condition where the urethral opening is located on the ventral (lower) side of the penis.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that epispadias and hypospadias are both urethral anomalies that require prompt evaluation and treatment to prevent potential complications, such as urinary tract infections or infertility.

**Correct Answer:** D.