**Question:** WHO definition of normal sperm count:

A. 15 million to 200 million sperm per milliliter of semen
B. The absence of sperm in the ejaculate
C. The presence of motile sperm in the semen following sexual intercourse
D. The presence of immotile sperm in the semen following sexual intercourse

**Correct Answer:** A. 15 million to 200 million sperm per milliliter of semen

**Core Concept:**
The WHO (World Health Organization) has provided a definition for the normal sperm count in a man's ejaculate. The normal range is determined based on the number of sperm per milliliter of semen.

**Why the Correct Answer is Right:**
The WHO defines a normal sperm count as the presence of a certain number of sperm (15 million to 200 million) per milliliter of semen. This range ensures that the ejaculate contains a sufficient number of sperm for fertilization to occur during sexual intercourse. A high sperm concentration indicates that the testes are producing a sufficient number of sperm, while a low sperm concentration could indicate a problem with sperm production or transport to the ejaculate.

**Why Each Wrong Option is Incorrect:**

A. The absence of sperm in the ejaculate (B) is not considered normal, as sperm are essential for fertility.
B. The absence of motile sperm in the semen following sexual intercourse (C) is not a definition of normal sperm count, as motility is not the sole determinant of fertility.
D. The presence of immotile sperm in the semen following sexual intercourse (D) is not a definition of normal sperm count, as immotile sperm are not capable of penetrating the female genital tract and fertilizing an egg.

**Clinical Pearl:**
Understanding the WHO definition of normal sperm count is essential for assessing a man's fertility potential. A normal sperm count indicates that the testes are producing sufficient sperm and that sperm are being transported to the ejaculate. Evaluating the motility, morphology, and concentration of sperm is crucial for determining an individual's fertility status.