Newborn disorders are quite distinctive among human diseases because (1) there is a major physiological change from foetal to neonatal life, (2) organs are still in their developing stage, and (3) foetuses are impacted by uterine environment conditions, such as intrauterine infection/inflammation. Any illness, impairment, or abnormal state that mostly affects infants and children—that is, those between the foetus and adolescence—is referred to as a childhood disease or disorder. Childhood is a time when both the child and the immediate environment undergo significant changes. The changes in a child's growth and development are so noticeable that it's almost as if the youngster is a series of unique but related individuals passing through childhood and adolescence. Changes in the environment occur as a child's and teenager's surroundings and contacts change from that of a completely dependent infant to that of a more independent child and adolescent. The health and sickness of children from conception to adolescence must be understood in the context of these changes.