Which of the following factor is NOT responsible for declining child sex ratio?

Higher life expectancy among females

The correct answer is option 3: Higher life expectancy among females

The declining child sex ratio refers to the decreasing number of girls per 1,000 boys in the age group of 0–6 years. The major factors responsible for this decline include:

• Sex-specific abortion – Parents choosing to abort a fetus based on its sex, usually if it's female.

• Neglect of girl babies in infancy – Less care, nutrition, and medical attention given to female infants.

• Female infanticide – The deliberate killing of girl infants.

However, higher life expectancy among females is not a factor in the declining child sex ratio. In fact, females generally tend to live longer than males, but this affects the overall sex ratio, not the child sex ratio.