Why are babies are different sizes?

Babies are different sizes due to a combination of genetic, environmental, and nutritional factors. Genetics play a significant role, as a child's size often reflects the heights and weights of their parents. Additionally, prenatal factors such as maternal health, nutrition, and the presence of any complications during pregnancy can influence fetal growth. Variations in gestational age at birth also contribute, as babies born earlier may be smaller than those born full-term.