X chromosome
One of the two sex chromosomes in humans; females have two X chromosomes, males have one
ex: A female inherits one X from each parent.
Y chromosome
The sex chromosome that determines male biological sex.
ex: Males have one X and one Y chromosome.
Testosterone
A male sex hormone responsible for the development of male reproductive tissues and secondary sex characteristics
ex: Testosterone levels rise in boys during puberty, causing voice deepening and muscle growth.
Puberty
The period of sexual maturation during which a person becomes capable of reproduction
ex: Girls may start menstruating and boys may experience a growth spurt.
Primary sex characteristics
The body structures directly involved in reproduction.
ex: Ovaries in females and testes in males.
Secondary sex characteristics
Physical traits that develop during puberty but are not directly involved in reproduction.
ex: Breast development in girls, facial hair in boys.
Menarche
The first menstrual period in girls
ex: Typically occurs around age 12-13 in the U.S.
AIDS (Acquired immune deficiency syndrome)
A life-threatening condition caused by the HIV virus, which weakens the immune system.
ex: People with AIDS are vulnerable to infections that a healthy immune system could normally fight off.
Sexual orientation
A person’s enduring sexual attraction toward members of the same, opposite, or both sexes.
ex: Heterosexual, homosexual, or bisexual orientation.
Aggression
Any physical or verbal behavior intended to harm someone physically or emotionally.
ex: Yelling at someone or hitting another person during an argument.
Gender roles
The expected behaviors, attitudes, and traits society considers appropriate for males and females.
ex: Men as breadwinners, women as caregivers.
Roles
The behaviors expected of a person in a particular social position.
ex: A teacher is expected to educate and guide students.
Gender identity
One’s personal sense of being male, female, or another gender.
ex: A person assigned female at birth may identify as male.
Social learning theory
Theory that we learn social behavior by observing and imitating others and through rewards/punishments.
ex: A child sees a sibling punished for aggressive behavior and avoids acting aggressively.
Gender typing
The process of adopting traditional male or female roles.
ex: A boy playing with trucks because society associates them with masculinity.
Transgender
A person whose gender identity differs from the sex they were assigned at birth.
ex: Someone assigned male at birth identifies as female.
Zygote
The fertilized egg, the first stage of prenatal development.
ex: A sperm and egg unite to form a zygote.
Embryo
The developing human organism from about 2 weeks to 8 weeks after fertilization.
ex: The heart begins to beat during the embryonic stage.
Fetus
The developing human from 9 weeks after conception to birth.
ex: Organs continue to mature during the fetal stage.
Teratogens
Agents like chemicals or viruses that can cause harm to a developing embryo or fetus.
ex: Alcohol or certain medications can be teratogens.
Fetal alcohol syndrome (FAS)
Physical and cognitive abnormalities in children caused by a pregnant mother’s heavy drinking.
ex: Children may have facial deformities and learning disabilities.
Habituation
Decreased responsiveness to a stimulus after repeated exposure.
ex: A baby stops reacting to a repeatedly shown toy.
Rooting reflex
A newborn’s tendency to turn the head toward a touch on the cheek.
ex: Helps the baby find the nipple for feeding.
Sucking reflex
A newborn reflex to suck on anything that touches the roof of their mouth.
ex: Enables a baby to feed.