Psychological development in the context of "Infants"

In psychology, developmental stage theories are theories that divide psychological development into distinct stages which are characterized by qualitative differences in behavior.

There are several different views about psychological and physical development and how they proceed throughout the life span. The two main psychological developmental theories include continuous and discontinuous development. In addition to individual differences in development, developmental psychologists generally agree that development occurs in an orderly way and in different areas simultaneously.

Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through cell proliferation and differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood.

In medicine, precocious puberty is puberty occurring at an unusually early age. In most cases, the process is normal in every aspect except the unusually early age and simply represents a variation of normal development. There is early development of secondary sex characters and gametogenesis also starts earlier. Precocious puberty is of two types: true precocious puberty and pseudoprecocious puberty. In a minority of children with precocious puberty, the early development is triggered by a disease such as a tumor or injury of the brain.

Even when there is no underlying disease, unusually early puberty can have adverse effects on social behavior and psychological development (having more mature knowledge than one's peers, feeling inadequate, trying to attend and establish friendships with older people, depression). Affected children also face shorter adult height potential and possible lifelong health risks. Central precocious puberty can be treated by suppressing the pituitary hormones that induce sex steroid production. The opposite condition is delayed puberty.