- The complex of male or female gonads, associated ducts, and external genitalia concerned with sexual reproduction.
- The system of organs involved with animal reproduction, especially sexual reproduction. The structure of animal reproductive systems depends on the type of fertilization (internal or external) and whether the animal lays eggs or bears live offspring. In mammals, the reproductive system consists mainly of the ovaries, fallopian tubes, uterus, and vagina in females and the testes, sperm ducts, and penis in males.
- The system of organs involved with the reproduction, especially the sexual reproduction, of plants and other complex multicellular organisms that are not animals. In flowering plants, the reproductive system consists of pistils and stamens. In conifers and most other gymnosperms, the reproductive system consists of male and female cones. The male gametes are produced directly from a cell in the pollen grain of these gymnosperms rather than in a distinct reproductive structure, while the female cones have ovules containing archegonia. In seedless plants (bryophytes and ferns), the reproductive system consists of archegonia and antheridia.