**Question:** The age by which most of the normal babies know their gender is -

A. 1-2 years
B. 2-3 years
C. 3-4 years
D. 4-5 years

**Core Concept:**

Phylogenetically, human infants exhibit a unique developmental milestone called "gender recognition" that involves the ability to differentiate between male and female individuals. This process is influenced by the maturation of the brain, particularly the development of the amygdala and the prefrontal cortex, which play a crucial role in social cognition and emotional processing.

**Why the Correct Answer is Right:**

The correct answer (D) refers to the age range between 4-5 years, which is when most infants can accurately identify their own gender. This development occurs due to the maturation of the brain, particularly the amygdala and prefrontal cortex, which are essential for social cognition and emotional processing. These areas are responsible for understanding social information, recognizing emotions, and making sense of social interactions.

**Why Each Wrong Option is Incorrect:**

A) At 1-2 years, infants are still in the early stages of cognitive development, lacking the understanding of gender identity and social cognition skills required for this milestone.

B) While the cognitive abilities may increase between 2-3 years, infants at this age do not have a clear understanding of their gender identity or the ability to differentiate between male and female individuals.

C) At 3-4 years, infants are still maturing cognitively, and the development of gender recognition is not yet well-established in this age range.

**Clinical Pearl:**

Understanding the development of gender recognition in children can help healthcare professionals assess and support children's cognitive development. It is essential to recognize that this milestone is influenced by the maturation of specific brain regions and is not a simple cognitive task but rather a complex process involving social cognition and emotional processing.