## **Core Concept**
The World Health Organization (WHO) provides criteria for normal semen analysis to assess male fertility. These criteria include parameters such as semen volume, sperm concentration, total sperm number, motility, and morphology. Understanding these criteria is essential for evaluating male fertility.

## **Why the Correct Answer is Right**
The correct answer is related to the specific criteria that are not essential according to the WHO for normal semen analysis. Typically, the WHO criteria for semen analysis include:
- Semen volume
- Sperm concentration
- Total sperm number
- Sperm motility
- Sperm morphology

## **Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because, without specifying what A is, we can't directly address it, but typically, semen volume is an essential criterion.
**Option B:** Similarly, this is incorrect as we lack specifics, but usually, sperm concentration is crucial.
**Option C:** This option's accuracy depends on what C represents; if it's related to a non-essential criterion, it might be correct, but we need specifics.
**Option D:** This would be incorrect if D represents one of the commonly accepted essential criteria like motility or morphology.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the WHO periodically updates its reference values for semen characteristics. For instance, the 2010 WHO criteria consider normal semen analysis parameters as follows: a semen volume of ≥1.5 mL, sperm concentration ≥15 million/mL, total sperm number ≥39 million per ejaculate, motility ≥40% with progressive movement, and morphology ≥4% with normal forms.

## **Correct Answer:** . Fructose concentration.