Heredity and environment play key roles in child development, affecting body size, eye color, and disease risk. A poor diet can cause tooth decay. As children grow, their senses develop, giving them greater awareness of their environment. Gross and fine motor skills improve as children get older.

Some toddlers experience sleep disturbances. Children should be given nutritious foods and encouraged to feed themselves. Homes should be childproofed to help keep children safe. Toilet training should not be attempted before a child is ready. Parents should provide comfortable clothes and teach good hygiene.