Carol Gilligan challenged existing models of moral development, such as Kohlberg's, by arguing they were biased toward male perspectives. Her seminal work, 'In a Different Voice,' specifically examined the moral development of girls and boys, highlighting how socialization leads to different moral orientations, such as an ethic of care versus an ethic of justice.

M.P. Horuik is noted for his developmental research focusing on the behavioral challenges faced by children. His study specifically examined children ranging from 21 months to 14 years of age, providing a longitudinal perspective on how behavioral issues manifest and evolve during critical developmental windows. This research is significant for understanding the normative versus non-normative behavior patterns in children and for developing strategies to support healthy psychological growth during these formative years.

A zygote is the initial cell formed when two gamete cells are joined by means of sexual reproduction. It represents the earliest developmental stage of the human organism, occurring immediately after fertilization and before the process of implantation and subsequent embryonic development begins.

Babbling is a critical stage in language acquisition where infants produce speech-like sounds, such as 'ba-ba' or 'da-da'. Although these sounds do not yet carry specific semantic meaning, they allow the infant to practice the motor skills necessary for speech production and to explore the phonemes present in their native language environment.

At the preconventional level of Kohlberg's theory of moral development, individuals base their moral judgments primarily on the immediate consequences of their actions. Behavior is considered 'good' if it avoids punishment and 'bad' if it leads to punishment. This stage reflects a self-centered perspective where moral reasoning is dictated by external authority rather than internalized principles or social norms.

Social referencing is a developmental process where infants look to trusted caregivers for emotional cues to determine how to react to unfamiliar people, objects, or situations. By observing the mother's positive or negative facial expressions, the infant learns whether a situation is safe or threatening.

In Erik Erikson's stages of psychosocial development, the first stage occurs during infancy, focusing on the conflict between trust and mistrust. When an infant's needs are consistently met by caregivers, they develop a sense of basic trust in the world. The successful resolution of this stage results in the development of the virtue of 'hope,' which provides the individual with the enduring belief that desires can be attained despite setbacks.

Erik Erikson is renowned for his theory of psychosocial development, which is one of the few frameworks that covers the entire human lifespan from infancy through old age. Unlike many of his contemporaries who focused primarily on childhood, Erikson identified eight distinct stages, each characterized by a unique psychosocial crisis that must be resolved to achieve healthy development and personal growth throughout the lifespan.

Teratogens are external agents that interfere with normal prenatal development, potentially leading to structural or functional abnormalities in the fetus. Common examples include alcohol, certain medications, nicotine, and infectious diseases. The impact of a teratogen often depends on the timing of exposure during pregnancy, as specific organs and systems are more vulnerable during critical periods of rapid development.

PKU stands for Phenylketonuria, a rare inherited genetic disorder. It is caused by a mutation in the gene that produces the enzyme phenylalanine hydroxylase, which is necessary to break down the amino acid phenylalanine. If left untreated, phenylalanine builds up to harmful levels in the body, potentially causing intellectual disabilities and other developmental issues. Early detection through newborn screening and strict dietary management are essential to prevent the adverse effects of this metabolic condition.