Physical Development is the process that begins in human infancy and continues into late adolescent concentrating on gross and fine motor skills as well as puberty. From the day a child is conceived heir growth is being charted, and it is done continuously. Infants and toddlers are categorized from the time they are born until the age of 2. A child's most critical growth period is before they are even born, when they're organs are being developed. In Spencer A. Rathus,'s book Childhood & Adolescence: Voyages in Development, which demonstrates the development of organs from 3 to 16 weeks. The chart begins with the heart and central nervous system at three weeks, 4-5 weeks heart, eyes, arms, and legs, 6-8 weeks ear, teeth, palate, and external genitalia, followed by the 9-16th week the brain. These newly conceived children are impacted on growth both physically and mentally, all beginning their parent's health stress, eating habits and overall health. "malnutrition in the mother, especially during their last trimester when the fetus should be making rapid gains in weight, has been linked to low birth weight, prematurity, stunted growth, retardation of brain development" (Rathus 91). A child's growth begins before the child is even conceived, and it is suggested that a mother should begin healthy and nutritious habits before planning a pregnancy, while an unexpected mother should begin right away to decrease any possible side effects of malnutrition.
"The average North American is 20 inches long and weighs 7 1/2 pounds," stated by John W. Santrock, author of Child Development. During the first couple of months, a newborn gains an average of 5 to 6 ounces per week and grows ¾ of an inch every month during their first year. By the time a child hits 2 years, he or she is at half of his eventual adult height, an average at the age of 2 is 32-35 inches. A child's height and weight is one of the most distinguishable feature of the physical development, however these infants and toddlers also grow mentally.