Sexual Differentiation Key Terms

Flashcards for reviewing vocabulary related to sexual differentiation.

α-fetoprotein

A protein found in the plasma of fetuses. In rodents, α-fetoprotein binds estrogens and prevents them from entering the brain.

5α-reductase

An enzyme that converts testosterone into dihydrotestosterone (DHT).

Activational effect

A temporary change in behavior resulting from the administration of a hormone to an adult animal.

Altricial

Referring to animals that are born in a very immature state and depend on maternal care, as human infants do.

Androgen insensitivity syndrome (AIS)

A syndrome caused by a mutation of the androgen receptor gene that renders tissues insensitive to androgenic hormones like testosterone. Affected XY individuals are phenotypic females, but they have internal testes and regressed internal genital structures.

Anti-müllerian hormone (AMH)

A protein hormone secreted by the fetal testis that inhibits Müllerian duct development.

Appetitive behavior

The second stage of mating behavior. It helps establish or maintain sexual interaction.

Aromatase

An enzyme that converts some androgens into estrogens.

Aromatization

The chemical reaction that converts testosterone to estradiol, and other androgens to other estrogens.

Aromatization hypothesis

The hypothesis that testicular androgens enter the brain and are converted there into estrogens to masculinize the developing nervous system in some rodents.

Castration

The removal of the gonads (testes or ovaries), leading to a loss of hormone production and reproductive capability.

Cloacal exstrophy

A rare congenital condition where the abdominal wall and part of the intestines are exposed outside the body, often associated with abnormalities in the urinary and reproductive organs.

Congenital adrenal hyperplasia (CAH)

A group of inherited disorders affecting the adrenal glands, leading to an overproduction of androgens and potential masculinization of female genitalia.

Coolidge effect

The phenomenon where animals (and humans) exhibit renewed sexual interest when introduced to a novel sexual partner, despite prior sexual satiation.

Copulation

The act of mating or sexual intercourse.

Copulatory lock

A mating behavior observed in some species where the male and female are temporarily physically locked together during copulation.

Dihydrotestosterone (DHT)

The 5α-reduced metabolite of testosterone; a potent androgen that is principally responsible for the masculinization of the external genitalia in mammalian sexual differentiation.

Ejaculation

The expulsion of semen from the male reproductive tract during orgasm.

Estrus

The period during which female animals are sexually receptive.

External fertilization

The process by which sperm fertilize eggs outside the female's body, as seen in many aquatic species.

Gamete

A reproductive cell (sperm or egg) that unites with another during fertilization to form a new organism.

Gender

The social and cultural roles, behaviors, and attributes that a given society considers appropriate for men and women.

Guevedoces

Literally, “eggs at 12” (in Spanish). A nickname for individuals who are raised as girls but at puberty change appearance and begin behaving as boys do.

Hermaphrodite

An individual possessing both male and female reproductive organs.

Indifferent gonads

The early stage of gonad development in embryos before sexual differentiation occurs.