Physical Growth During Infancy and Toddlerhood

Children grow faster during the first three years of life—especially during the first few months—than at any other time. This rapid growth gradually slows during the second and third years.

At most ages, boys are typically slightly taller and heavier than girls, which reflects a consistent pattern in early childhood growth.

As a baby grows into a toddler, body shape and proportions change noticeably. A three-year-old is typically leaner and more muscular compared to a chubby, potbellied one-year-old.

The genes an infant inherits strongly influence whether the child will be tall or short, thin or stocky, or somewhere in between.

This genetic influence interacts with environmental factors, such as nutrition and living conditions, to shape physical growth.

Teething is a natural milestone for babies, and most babies have their first tooth at around six months.

By their first birthday, most babies have six to eight teeth. By about two and a half years, most children have a full set of twenty milk teeth.