**Question:** First sign of male puberty is -

A. Increase in body hair
B. Enlargement of testes
C. Deepening of voice
D. Growth spurt

**Core Concept:** Puberty is the process of physical and psychological maturation that occurs during adolescence, marked by the onset of secondary sexual characteristics. In males, the primary reproductive organ is the testes, which secrete testosterone, a hormone responsible for male characteristics.

**Why the Correct Answer is Right:** The first sign of male puberty is the enlargement of testes (Option B), which is a physiological response to increased Leydig cell activity. Leydig cells are responsible for producing testosterone, the primary hormone that drives male sexual development. As testosterone levels rise, secondary male sexual characteristics such as body hair, voice deepening, and growth spurt are initiated.

**Why Each Wrong Option is Incorrect:**

A. Increase in body hair (Option A) is a secondary sign of puberty, occurring later due to increased testosterone levels.

C. Deepening of voice (Option C) is a result of vocal cords becoming longer due to increased laryngeal cartilage growth and muscle development, not directly related to testes enlargement or testosterone production.

D. Growth spurt (Option D) is a result of growth hormone surge during puberty, not directly related to testes enlargement or testosterone production.

**Clinical Pearl:** The sequence of male pubertal changes starts with testes enlargement, followed by body hair development, voice deepening, and finally growth spurt. This progression ensures that secondary sexual characteristics develop in a coordinated manner, reflecting the maturation process.

**Correct Answer:** B. Enlargement of testes