Child development involves the biological, psychological and emotional changes that occur in human beings between birth and the conclusion of adolescence. In the course of development, the individual human progresses from dependency to increasing autonomy. It is a continuous process with a predictable sequence, yet has a unique course for every child. It does not progress at the same rate and each stage is affected by the preceding developmental experiences. Promoting child development through parental training, among other factors, promotes excellent rates of child development.[3] Parents play a large role in a child's activities, socialization, and development. Having multiple parents can add stability to a child's life and therefore encourage healthy development. Another influential factor in children's development is the quality of their care.