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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.

Sex organs are typically differentiated into male and female types. In humans, the male sex organs include the testes, penis, and prostate gland; the female sex organs include the ovaries, fallopian tubes, uterus, cervix, vagina, and vulva.

In animals (including humans), the testis in the male and the ovary in the female are called the primary sex organs. All other sex-related organs are called secondary sex organs, divided between internal and external sex organs. External sex organs include the genitals or external genitalia, visible at birth in both sexes.

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.

Together, the sex organs constitute an organism's reproductive system.

Flowers That Look Like Vaginas: Nature’s Unique Marvels

1. Poppy Plant

The opium poppy, scientifically known as Papaver, is an annual plant with large, lobed leaves and showy flowers. These blooms, in shades of red, pink, white, orange, and purple, oddly resemble a certain part of the female anatomy. Read more about Poppy Plant click here

2. African Tulip Flower

The African tulip, a perennial herbaceous plant growing from a bulb, is a striking addition to any garden. Its slender leaves give rise to clusters of red, orange, or yellow flowers, surprisingly similar to a woman’s form. Read more information about African Tulip Flower

3. Butterfly Pea

The Butterfly Pea plant is a marvel, with trifoliate leaves and striking blue or purple flowers about 1 to 2 inches in diameter. You’ll be amazed at how closely these flowers resemble a specific part of female anatomy.

4. Venus Flytrap

The Venus flytrap is extraordinary. It forms a rosette of long, pointed leaves growing from a short stem. Each leaf is divided into a long, narrow “blade” and a short, triangular “lobe,” creating an uncanny resemblance.

Evolution

It is hard to find a common origin for gonads but, gonads most likely evolved independently several times. At first testes and ovaries evolved due to natural selection.

A consensus has emerged that sexual selection represents a primary factor for genital evolution. Male genitalia show traits of divergent evolution that are driven by sexual selection.

Animals

Mammals

The visible portion of the mammalian genitals for males consists of the scrotum and penis; for females, it consists of the vulva (labia, clitoris, etc.).

In placental mammals, females have two genital orifices, the vagina and urethra, while males have only one, the urethra. Male and female genitals have many nerve endings, resulting in pleasurable and highly sensitive touch. In most human societies, particularly in conservative ones, exposure of the genitals is considered a public indecency.

In humans, sex organs include:

Male	Female
External Penis Foreskin Frenulum Shaft Glans Scrotum Internal Prostate Bulbourethral glands Epididymis Seminal vesicles Testicles	External Vulva Hymen Clitoris Frenulum Glans Body Hood Labia Labia majora Labia minora Bartholin's glands Skene's glands Internal Fallopian tubes Ovaries Uterus Cervix Vagina

Development

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (August 2021) (Learn how and when to remove this message)

In typical prenatal development, sex organs originate from a common primordium during early gestation and differentiate into male or female sexes. The SRY gene, usually located on the Y chromosome and encoding the testis determining factor, determines the direction of the differentiation. The absence of it allows the gonads to continue to develop into ovaries.

The development of the internal, and external reproductive organs is determined by hormones produced by certain fetal gonads (ovaries or testes) and the cells' response to them. The initial appearance of the fetal genitalia looks female-like: a pair of urogenital folds with a small protuberance in the middle, and the urethra behind the protuberance. If the fetus has testes and the testes produce testosterone, and if the cells of the genitals respond to the testosterone, the outer urogenital folds swell and fuse in the midline to produce the scrotum; the protuberance grows larger and straighter to form the penis; the inner urogenital swellings grow, wrap around the penis, and fuse in the midline to form the penile urethra. Each sex organ in one sex has a homologous counterpart.

The process of sexual differentiation includes the development of secondary sexual characteristics, such as patterns of pubic and facial hair and female breasts that emerge at puberty.

Because of the strong sexual selection affecting the structure and function of genitalia, they form an organ system that evolves rapidly. A great variety of genital form and function may therefore be found among animals.

Cloacae

In many other animals a single posterior orifice, called the cloaca, serves as the only opening for the reproductive, digestive, and urinary tracts (if present). All amphibians, birds, reptiles, some fish, and a few mammals (monotremes, tenrecs, golden moles, and marsupial moles) have this orifice, from which they excrete both urine and feces in addition to serving reproductive functions. Excretory systems with analogous purpose in certain invertebrates are also sometimes referred to as cloacae.

Insects

The organs concerned with insect mating and the deposition of eggs are known collectively as the external genitalia, although they may be largely internal; their components are very diverse in form.

Slugs and snails

The reproductive system of gastropods (slugs and snails) varies greatly from one group to another.

Planaria

Planaria are flat worms widely used in biological research. There are sexual and asexual planaria. Sexual planaria are hermaphrodites, possessing both testicles and ovaries. Each planarian transports its excretion to the other planarian, giving and receiving sperm.

Plants

In most plant species, an individual has both male and female sex organs.

The life cycle of land plants involves alternation of generations between a sporophyte and a haploid gametophyte. The gametophyte produces sperm or egg cells by mitosis. The sporophyte produces spores by meiosis which in turn develop into gametophytes. Any sex organs that are produced by the plant will develop on the gametophyte. The seed plants, which include conifers and flowering plants, have small gametophytes that develop inside the pollen grains (male) and the ovule (female).

Flowers

In flowering plants, the flowers contain the sex organs.

Sexual reproduction in flowering plants involves the union of the male and female germ cells, sperm and egg cells respectively. Pollen is produced in stamens and is carried to the pistil, which has the ovary at its base where fertilization can take place. Within each pollen grain is a male gametophyte which consists of only three cells. In most flowering plants, the female gametophyte within the ovule consists of only seven cells. Thus there are no sex organs as such.

Fungi

The sex organs in fungi are called gametangia. In some fungi, the sex organs are indistinguishable from each other but, in other cases, male and female sex organs are clearly different.

Similar gametangia that are similar are called isogametangia. While male and female gametangia are called heterogametangia, which occurs in the majority of fungi.

See also

• Andrology
• Emasculation
• Genital modification and mutilation
• Hermaphrodite
• Human sexuality
• Hysterectomy
• Intimate part
• Obstetrics and gynaecology
• Oophorectomy
• Orchiectomy

References

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4. "Mosses and Ferns". Biology.clc.uc.edu. 16 March 2001. Archived from the original on 28 July 2012. Retrieved 1 August 2012.
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9. Langerhans, R. Brian; Anderson, Christopher M.; Heinen-Kay, Justa L. (6 September 2016). "Causes and Consequences of Genital Evolution". Integrative and Comparative Biology. 56 (4): 741–751. doi:10.1093/icb/icw101. ISSN 1540-7063. PMID 27600556.
10. Simmons, Leigh W. (2014). "Sexual selection and genital evolution". Austral Entomology. 53 (1): 1–17. doi:10.1111/aen.12053. ISSN 2052-1758. S2CID 53690631.
11. Marvalee H. Wake (1992). Hyman's Comparative Vertebrate Anatomy. University of Chicago Press. p. 583. ISBN 978-0-226-87013-7.
12. Brigitta Olsen (15 November 2009). Daphne's Dance: True Tales in the Evolution of Woman's Sexual Awareness. Brigitta Olsen. p. 9. ISBN 978-0-9842117-0-8.
13. Anita Allen (November 2011). Unpopular Privacy: What Must We Hide?. Oxford University Press, US. p. 219. ISBN 978-0-19-514137-5.
14. Hosken, David J., and Paula Stockley."Sexual selection and genital evolution." Archived 12 October 2017 at the Wayback Machine Trends in Ecology & Evolution 19.2 (2004): 87-93.
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16. Schilthuizen, M. 2014. Nature's Nether Regions: What the Sex Lives of Bugs, Birds, and Beasts Tell Us About Evolution, Biodiversity, and Ourselves Archived 14 June 2023 at the Wayback Machine. Penguin USA
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19. Purves, William K.; Sadava, David E.; Orians, Gordon H.; Heller, H. Craig (2001). Life: The Science of Biology. Macmillan. p. 176. ISBN 978-0-7167-3873-2.
20. Pal, Nishant (6 December 2021). Plant Biology. Independently Published. ISBN 979-8-7799-0473-5. Archived from the original on 10 April 2023. Retrieved 25 March 2023.
21. Purves, William K.; Sadava, David E.; Orians, Gordon H.; Heller, H. Craig (2001). Life: The Science of Biology. Macmillan. p. 665. ISBN 978-0-7167-3873-2.
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Further reading

• Leonard, Janet L.; Córdoba-Aguilar, Alex (2010). The Evolution of Primary Sexual Characters in Animals. Oxford: Oxford University Press. ISBN 978-0199717033.

• Sex organs