A parenting style characterized by a parent’s indifference to a child, including a lack of emotional involvement.

Fraternal twins who develop from two eggs inseminated by two sperm, and are as genetically similar as any sibling pair.

The combining of consonants with vowels typically displayed at the age of 4 to 6 months.

Production of vowel-like sounds by infants, often repeated in a joyful manner.

Specific time frame in which an organism is sensitive to environmental factors, and certain behaviors and abilities are readily shaped or altered by events or experiences.

The male hormones secreted by the testes in males.

Body characteristics, such as pubic hair, underarm hair, and enlarged breasts, that develop in puberty but are not associated with reproduction.

A collection of ideas that represents a basic unit of understanding.

Inherited threadlike structures composed of deoxyribonucleic acid (DNA).

Two-word phrases typically used by infants around the age of 18 months.

The psychological or mental guidelines that dictate how to be masculine and feminine.

The female hormone secreted primarily by the ovaries in females.

The dimension of masculinity and femininity based on social, cultural, and psychological characteristics.

Piaget’s stage of cognitive development during which children can start to use language to explore and understand their worlds.

An androgen produced by the testes.

The point at which menstruation begins.

A rigid parenting style characterized by strict rules and poor communication skills.

An individual who seeks or undergoes a social transition to the other gender, and who may make changes to his or her body through surgery and medical treatment.

A parenting style characterized by high expectations, strong support, and respect for children.

The observable expression or characteristics of one's genetic inheritance.

Characteristic differences in behavioral patterns and emotional reactions that are evident from birth.

The ability to think in the abstract and create associations among concepts.

A research design that examines people of different ages at a single point in time.

Refers to people whose gender identity and expression do not typically match the gender assigned to them at birth.

The period of development during which the body changes and becomes sexually mature and capable of reproduction.

Ambiguous or inconsistent biological indicators of male or female in the sexual structures and organs.

A field of psychology that examines physical, cognitive, and socioemotional changes across the life span.

A boy’s first ejaculation.

Pushing children to go just beyond what they are competent and comfortable doing, while providing help in a decreasing manner.

Kohlberg’s stage of moral development that determines right and wrong from the expectations of society and important others.

A parenting style characterized by low demands of children and few limitations.

A single cell formed by the union of a sperm cell and egg.

The process by which the lens changes shape in order to focus on images near and far.

Piaget’s stage of cognitive development during which infants use their sensory capabilities and motor skills to learn about the surrounding world.

A field of study that examines the processes involved in the development of phenotypes.

A molecule that provides the instructions for the development and production of cells.

Kohlberg’s stage of moral development in which right and wrong are determined by the individual’s beliefs about morality, which sometimes do not coincide with society’s rules and regulations.

A phase of life between 18 and 25 years that includes exploration and opportunity.

The tendency to cross gender-role boundaries, exhibiting behaviors associated with both genders.

A milestone of the sensorimotor stage of cognitive development; an infant’s realization that objects and people still exist even when out of sight or touch.

Organs associated with reproduction, including the ovaries, uterus, vagina, penis, scrotum, and testes.

The collection of actions, beliefs, and characteristics that a culture associates with masculinity and femininity.

A sense of self based on values, beliefs, and goals.

Refers to the unchanging properties of volume, mass, or amount in relation to appearance.

Specified segment of a DNA molecule.

The time when a woman no longer ovulates, her menstrual cycle stops, and she is no longer capable of reproduction.

One of a pair of genes that is dominated by the other gene in the pair.

A research design that examines groups of people of different ages, following them across time.

Only able to imagine the world from one’s own perspective.

Piaget’s stage of cognitive development during which children begin to think more logically, but mainly in reference to concrete objects and circumstances.

The degree to which an infant feels an emotional connection with primary caregivers.

Identical twins who develop from one egg inseminated at conception, which then splits into two separate cells.

The unborn human from the beginning of the 3rd week of pregnancy, lasting through the 8th week of prenatal development.

The unborn human from 2 months following conception to birth.

One of a pair of genes that has power over the expression of an inherited characteristic.

Delays in development that result from moderate to heavy alcohol use during pregnancy.

An individual’s complete collection of genes.

The transition period between late childhood and early adulthood.

Kohlberg’s stage of moral development in which a person, usually a child, focuses on the consequences of behaviors, good or bad, and is concerned with avoiding punishment.

Knowledge gained through learning and experience.

The feeling or sense of being either male or female, and compatibility, contentment, and conformity with one’s gender.

A research design that examines one sample of people over a period of time to determine age-related changes.

Using existing information and ideas to understand new knowledge and experiences.

Piaget’s stage of cognitive development during which children begin to think more logically and systematically.

Environmental agents that can damage the growing zygote, embryo, or fetus.

Physical growth beginning with conception and ending when the body stops growing.