**Core Concept**
The height of a newborn undergoes significant growth and development during the first few years of life, with certain milestones marking key periods of rapid expansion. This question pertains to the doubling of a newborn's height, a crucial aspect of pediatric growth and development.

**Why the Correct Answer is Right**
The height of a newborn typically doubles by the age of 4-5 months. This period of rapid growth is influenced by the maturation of the hypothalamic-pituitary-adrenal axis and the increase in growth hormone production. The growth hormone stimulates the production of insulin-like growth factor-1 (IGF-1), which in turn promotes cell proliferation and differentiation in the growth plates of long bones.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the height of a newborn does not double at birth or shortly after.
**Option B:** This option is incorrect because the height of a newborn does not double at 1-2 years of age, although growth does continue at a slower rate during this period.
**Option C:** This option is incorrect because the height of a newborn does not double at 6-7 years of age, although growth continues at a steady rate during childhood.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the growth rate of a newborn slows down after the first few months of life, with growth velocity gradually decreasing until puberty. Understanding these growth patterns is crucial for pediatricians to monitor and assess the development of children.

**Correct Answer: C. 6-7 years of age is incorrect, the correct answer is not given, but the doubling of height typically occurs around 4-5 months of age**