Sex organ

A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting gametes, as well as facilitating fertilization and supporting the development and birth of offspring. Sex organs are found in many species of animals and plants, with their features varying depending on the species. The sex organs constitute the organism's reproductive system.

In humans and other mammals the sex organs are typically differentiated into male and female types. The primary sex organs are the ovaries in females, and the testicles in males. Secondary sex organs include the clitoris, oviducts (fallopian tubes), and vagina in females, and in males the epididymides, and penis. The outer parts are known as the genitals or external genitalia, visible at birth in both sexes, while the inner parts that are always hidden are referred to as internal genitalia.

In plants, male reproductive structures include stamens in flowering plants, which produce pollen. Female reproductive structures, such as pistils in flowering plants, produce ovules and receive pollen for fertilization. Mosses, ferns, and some similar plants have gametangia for reproductive organs, which are part of the gametophyte. The flowers of flowering plants produce pollen and egg cells, but the sex organs themselves are inside the gametophytes within the pollen and the ovule. Coniferous plants likewise produce their sexually reproductive structures within the gametophytes contained within the cones and pollen. The cones and pollen are not themselves sexual organs.