**Question:** False regarding complete feminization is:

A. The ovaries are the primary sex organs responsible for female sex characteristics.
B. Testosterone is the primary hormone responsible for male sex characteristics.
C. Androgen receptors are exclusively expressed in male tissues.
D. Complete feminization occurs in cases of elevated testosterone levels.

**Correct Answer:** **D. Complete feminization occurs in cases of elevated testosterone levels.**

**Core Concept:** Complete feminization refers to the development of female sex characteristics in individuals with XY chromosomes due to the presence of elevated testosterone levels. Testosterone is a sex hormone produced by Leydig cells in the testes and is responsible for male sex characteristics.

**Why the Correct Answer is Right:**

In cases of complete feminization, the primary sex organs, the ovaries, secrete excessive amounts of estrogen and inhibin, which suppresses the production of testosterone by Leydig cells. As a result, testosterone levels decrease, leading to the development of female sex characteristics despite the presence of XY chromosomes.

**Why Each Wrong Option is Incorrect:**

A. The statement that the ovaries are the primary sex organs responsible for female sex characteristics is partially correct. However, it fails to mention the role of elevated estrogen and inhibin levels in the development of female sex characteristics.

B. Testosterone is not responsible for complete feminization. Elevated testosterone levels would lead to male sex characteristics. Instead, the issue lies in the suppressed testosterone production due to the mentioned factors (excess estrogen, inhibin) from the ovaries.

C. The statement that androgen receptors are exclusively expressed in male tissues is incorrect. Androgen receptors can be found in both male and female tissues, allowing the effects of androgens like testosterone to influence both sexes.

D. Complete feminization occurs due to elevated testosterone levels, not decreased testosterone levels. As mentioned earlier, the issue lies in the suppressed testosterone production by Leydig cells.

**Clinical Pearl:**

In cases of complete feminization, evaluating the hormonal profile (including testosterone, estrogen, and inhibin levels) is crucial to diagnose the underlying cause, such as genetic syndromes like 46,XY Klinefelter syndrome or disorders involving impaired gonadal function. Adequate understanding of the hormonal imbalances can guide treatment options and improve diagnostic accuracy.