gamete A reproductive cell; that is, a sperm or ovum that can produce a new individual if it combines with a gamete from the other sex to make a zygote.

gender differences Differences in the roles and behaviors of males and females that are prescribed by the culture.

gender identity A person’s acceptance of the roles and behaviors that society associates with the biological categories of male and female.

gender schema A cognitive concept or general belief based on one’s experiences—in this case, a child’s understanding of sex differences.

gene A small section of a chromosome; the basic unit for the transmission of heredity. A gene consists of a string of chemicals that provide instructions for the cell to manufacture certain proteins.

general intelligence (g) The idea of g assumes that intelligence is one basic trait, underlying all cognitive abilities. According to this concept, people have varying levels of this general ability.

generational forgetting The idea that each new generation forgets what the previous generation learned. As used here, the term refers to knowledge about the harm drugs can do.

generativity versus stagnation The seventh of Erikson’s eight stages of development. Adults seek to be productive in a caring way, perhaps through art, caregiving, and employment.

genetic clock A purported mechanism in the DNA of cells that regulates the aging process by triggering hormonal changes and controlling cellular reproduction and repair.

genetic counseling Consultation and testing by trained experts that enable individuals to learn about their genetic heritage, including harmful conditions that they might pass along to any children they may conceive.

genome The full set of genes that are the instructions to make an individual member of a certain species.

genotype An organism’s entire genetic inheritance, or genetic potential.

germinal period The first two weeks of prenatal development after conception, characterized by rapid cell division and the beginning of cell differentiation.

gonads The paired sex glands (ovaries in females, testicles in males). The gonads produce hormones and gametes.

grammar All the methods—word order, verb forms, and so on—that languages use to communicate meaning, apart from the words themselves.

grief The deep sorrow that people feel at the death of another. Grief is personal and unpredictable.

gross motor skills Physical abilities involving large body movements, such as walking and jumping. (The word gross here means “big.”)

growth spurt The relatively sudden and rapid physical growth that occurs during puberty. Each body part increases in size on a schedule: Weight usually precedes height, and growth of the limbs precedes growth of the torso.

guided participation The process by which people learn from others who guide their experiences and explorations.