An important aspect of parenting is understanding the changes your child will encounter during growth and development. As children advance through a sequence of growth stages they may face several challenges and relatively common problems. Although no children are exactly alike, there are universally accepted theories of human development and growth patterns most share. Children not only vary in physical appearance, they also express differences socially and mentally, as well as through personality and behaviour. How children interact with others and respond to their environment also changes throughout the developmental stages. Generally, these changes occur in an orderly manner; however, the rate of progression varies among children. Gaining an understanding for the series of development helps prepare parents to provide the proper care and attention their child needs.