A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely:

• Male: penis (notably the glans penis and foreskin), testicles, scrotum, prostate, seminal vesicles, epididymis, Cowper's glands
• Female: vulva (notably the clitoris), vagina (notably the cervix), labia, uterus, Fallopian tubes, ovaries, Skene's glands, Bartholin's glands.

More generally and popularly, the term sex organ refers to any part of the body involved in erotic pleasure. The larger list would certainly include the anus for either sex, the prepuce, the breasts (especially the nipples) for females, and the nipples for males.

The Latin term genitalia is used to describe the sex organs, and in the English language this term and genital area are most often used to describe the externally visible sex organs or external genitalia: in males the penis and scrotum, in females the vulva. The other parts of the sex organs are called the internal genitalia.

A gonad is a sex organ that produces gametes, specifically the testes or ovaries in humans.

Organs of sexual anatomy originate from a common anlage and differentiate into male or female sex organs. Each sexual organ in one sex has a homologous counterpart in the other one. See a list of homologues of the human reproductive system.

Anatomical terms related to sex

The following is list of anatomical terms related to sex and sexuality:

• anus -- areola
• Bartholin's gland -- breast -- bulbocavernosus muscle -- bulbospongiosus muscle -- bulbourethral gland
• cervix -- clitoris -- common penile artery -- corona glandis -- corpora cavernosa -- corpus cavernosum -- corpus spongiosum -- Cowper's glands-- cremaster muscle
• dartos muscle -- ductus deferens
• ejaculatory duct -- endometrium -- epididymis
• Fallopian tube -- foreskin -- frenulum -- frenulum preputii penis -- frenulum labiorum pudendi -- frenulum clitoridis -- frenum -- fundiform ligament
• G-spot -- Gartner's duct -- genital tubercle -- genitofemoral nerve -- glans -- glans penis -- Gräfenberg spot
• hymen
• internal pudendal artery -- ischiocavernosus muscle
• labia -- labia majora -- labia minora
• mammae -- mammary gland -- meatus -- mons veneris -- Mullerian duct
• nipple
• ovary -- ovum -- oviducts
• penis -- penile suspensory ligament -- perineum -- prepuce -- prostate -- pubic hair -- pubic symphysis -- pubococcygeus muscle -- pudendal nerve
• raphe -- rectum -- ridged band
• scrotum -- seminal vesicles -- semeniferous tubules -- Skene's glands -- sperm -- spermatic cord -- sphincter urethrae membranaceae -- splanchnic nerves
• testes -- testicle -- tunica albuginea
• urethra -- urethral sponge -- urogenital diaphragm -- uterus
• vas deferens -- vagina -- vesiculae seminales -- vomeronasal organ -- vulva
• Wolffian duct

See also: sex, human sexuality, sexual behavior, Obstetrics and gynecology, circumcision, castration, intersex, List of transgender-related topics, intimate parts, secondary sex characteristics, body modification, genital modification and mutilation, Sexual fetishism