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57-473: In mammals, the major organs of the reproductive system include the external genitalia ( penis and vulva ) as well as a number of internal organs, including the gamete -producing gonads (testicles and ovaries). Diseases of the human reproductive system are very common and widespread, particularly communicable sexually transmitted infections . Most other vertebrates have similar reproductive systems consisting of gonads, ducts, and openings. However, there

114-472: 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 testicles) and

171-403: 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. Penile and clitoral structures are present in some birds and many reptiles. Sexing teleost fish

228-402: A large crest). The penises of even-toed ungulates have an S-shape at rest and lie in a pocket under the skin on the belly. The corpora cavernosa are only slightly developed; and an erection mainly causes this curvature to extend, which leads to an extension, but not a thickening, of the penis . Cetaceans have similar penises. In some even-toed ungulates, the penis contains a structure called

285-418: A modified arm called a hectocotylus . That in turn is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the "penis" is long and able to extend beyond the mantle cavity and transfer the spermatophores directly to the female. Most insects reproduce oviparously , i.e. by laying eggs . The eggs are produced by the female in a pair of ovaries . Sperm , produced by

342-411: A primary factor for genital evolution. Male genitalia show traits of divergent evolution that are driven by sexual selection. The visible portion of eutherian mammalian genitals for males consists of the penis and scrotum ; for females, it consists of the vulva . In placental mammals , females have two genital orifices, the vaginal and urethral openings , while males have only one for

399-544: A specific order during puberty and varies but may follow this process. Boys today since 2010 have started puberty at 11 while boys in the 1970s didn't began to develop until age 12, today youths experience facial hair a year earlier than males in the 1970s [1]  : Although this order is commonly seen, it can vary widely, with some facial hair starting from the chin and up towards the sideburns. As with most human biological processes, this specific order may vary depending on one's genetic heritage or environment. Depending on

456-547: A unique prepenial scrotum. The 15 mm ( 5 ⁄ 8  in) long newborn joey instinctively crawls and wriggles the 15 cm (6 in), while clinging to fur, on the way to its mother's pouch. In regards to males, the mammalian penis has a similar structure in reptiles and a small percentage of birds while the scrotum is only present in mammals. Regarding females, the vulva is unique to mammals with no homologue in birds, reptiles, amphibians, or fish. The clitoris, however, can be found in some reptiles and birds. In place of

513-533: Is a great diversity of physical adaptations as well as reproductive strategies in every group of vertebrates. Vertebrates share key elements of their reproductive systems. They all have gamete-producing organs known as gonads . In females, these gonads are then connected by oviducts to an opening to the outside of the body, typically the cloaca, but sometimes to a unique pore such as a vagina . The human reproductive system usually involves internal fertilization by sexual intercourse . During this process,

570-420: Is a series of organs located outside of the body and around the pelvic region of a male that contribute towards the reproduction process. The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum. The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place in

627-399: Is also responsible for the development of physical characteristics in men such as facial hair and a deep voice. The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva , which leads to

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684-443: Is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph and the anamorph . Environmental conditions trigger genetically determined developmental states that lead to

741-612: Is determined by the shape of a fleshy tube behind the anus known as genital papilla . 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. The reproductive system of gastropods (slugs and snails) varies greatly from one group to another. 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

798-461: Is forbidden . Amish men grow beards after marriage, but continue to shave their moustaches in order to avoid historical associations with military facial hair due to their pacifistic beliefs. In Sikhism , one of the Five Ks followed by Khalsa Sikhs is kesh , which forbids the cutting or shaving of hair, both scalp and facial. Women typically have little hair on the face, apart from eyebrows and

855-399: Is known as pregnancy in humans. Gestation ends with childbirth , delivery following labor . Labor consists of the muscles of the uterus contracting, the cervix dilating , and the baby passing out the vagina (the female genital organ). Human's babies and children are nearly helpless and require high levels of parental care for many years. One important type of parental care is the use of

912-470: Is lubricated by mucus secreted by the Bartholin's glands . The vagina is attached to the uterus through the cervix , while the uterus is attached to the ovaries via the fallopian tubes . Each ovary contains hundreds of ova (singular ovum ). Approximately every 28 days , the pituitary gland releases a hormone that stimulates some of the ova to develop and grow. One ovum is released and it passes through

969-426: Is produced in stamens and is carried to the pistil or carpel , which has the ovule 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. The sex organs in fungi are known as gametangia . In some fungi,

1026-571: Is referred to as being "clean-shaven". The term whiskers , when used to refer to human facial hair, indicates the hair on the chin and cheeks. Women are also capable of developing facial hair, especially after menopause , though typically significantly less than men. Women with lots of facial hair, the extreme being bearded ladies , have been considered as freaks by society and sometimes been part of circuses . Trans men typically develop more facial hair while undergoing masculinizing hormone therapy as part of their wider gender transition. In

1083-582: Is typically a secondary sex characteristic of human males . Men typically start developing facial hair in the later stages of puberty or adolescence , at around fourteen years of age, and most do not finish developing a full adult beard until around sixteen or later. However, large variations can occur; boys as young as ten have also been known to develop facial hair, and some men do not produce much facial hair at all. Men may style their facial hair into beards , moustaches , goatees or sideburns ; many others completely shave their facial hair and this

1140-434: Is unique in that the female has two vaginae, both of which open externally through one orifice but lead to different compartments within the uterus; males usually have a two-pronged penis , which corresponds to the females' two vaginae. Marsupials typically develop their offspring in an external pouch containing teats to which their newborn young ( joeys ) attach themselves for post uterine development. Also, marsupials have

1197-482: 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 . The primary sex organs are

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1254-423: The gonads , a pair of internal sex organs, which diverge into testicles following male development or into ovaries following female development. As primary sex organs, gonads generate reproductive gametes containing inheritable DNA . They also produce most of the primary hormones that affect sexual development, and regulate other sexual organs and sexually differentiated behaviors. Secondary sex organs are

1311-531: The mammary glands in the female breasts to nurse the baby. The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the offspring until birth. The male reproductive system has one function, and it is to produce and deposit sperm. Humans have a high level of sexual differentiation . In addition to differences in nearly every reproductive organ, numerous differences typically occur in secondary sexual characteristics . The male reproductive system

1368-404: The penis , urethra , vas deferens , and Cowper's gland . Major secondary sex characteristics include larger, more muscular stature, deepened voice, facial and body hair , broad shoulders, and development of an Adam's apple . An important sexual hormone of males is androgen , and particularly testosterone . The testes release a hormone that controls the development of sperm. This hormone

1425-418: The testicles , which are housed in the temperature regulating scrotum , immature sperm then travel to the epididymides for development and storage. The second category is the ejaculatory fluid-producing glands which include the seminal vesicles , prostate , and the vasa deferentia . The final category are those used for copulation, and deposition of the spermatozoa ( sperm ) within the male, these include

1482-409: The urethral process. Male and female birds have a cloaca , an opening through which eggs, sperm, and wastes pass. Intercourse is performed by pressing the lips of the cloacae together, which is sometimes known as an intromittent organ which is known as a phallus that is analogous to the mammals' penis . The female lays amniotic eggs in which the young fetus continues to develop after it leaves

1539-763: The vellus hair that covers most of the body. However, in some cases, women have noticeable facial hair growth, most commonly after menopause. Excessive hairiness (especially facially) is known as hirsutism and is usually an indication of atypical hormonal variation. Many women depilate facial hair that appears, as considerable social stigma is associated with facial hair on women, and freak shows and circuses have historically displayed bearded women . Many women globally choose to totally remove their facial hair by means of electrolysis (permanent) or laser hair removal (semi-permanent). Adult orangutans have varying degrees of facial hair. In chimpanzees and gorillas , facial and body hair become sparser in adulthood due to

1596-611: The West in the nineteenth century, most men maintained some facial hair. According to a 1976 study by University of Washington economist Dwight Robinson, who reviewed illustrations in the Illustrated London News , facial hair peaked in the 1880s (90%). The wearing of beards dropped significantly, although mustaches remained popular until the 1940s. The moustache forms its own stage in the development of facial hair in adolescent males. Facial hair in males does not always appear in

1653-549: The abdomen. The genital opening is usually located on the underside of the second abdominal segment. In most species, the male transfers sperm to the female in a package, or spermatophore . Complex courtship rituals have evolved in many arachnids to ensure the safe delivery of the sperm to the female. Arachnids usually lay yolky eggs , which hatch into immatures that resemble adults. Scorpions, however, are either ovoviviparous or viviparous , depending on species, and bear live young. Among all living organisms, flowers , which are

1710-400: The ages of 6 and 12 months for both males and females, although this can be delayed until up to two years of age for some large breeds. The mare's reproductive system is responsible for controlling gestation, birth, and lactation, as well as her estrous cycle and mating behavior. The stallion's reproductive system is responsible for his sexual behavior and secondary sex characteristics (such as

1767-399: 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

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1824-501: The cloaca of reptiles. Most male reptiles have copulatory organs, which are usually retracted or inverted and stored inside the body. In turtles and crocodilians, the male has a single median penis-like organ, while male snakes and lizards each possess a pair of penis-like organs . Most amphibians exhibit external fertilization of eggs, typically within the water, though some amphibians such as caecilians have internal fertilization. All have paired, internal gonads, connected by ducts to

1881-530: The cloaca. Fish exhibit a wide range of different reproductive strategies. Most fish, however, are oviparous and exhibit external fertilization. In this process, females use their cloaca to release large quantities of their gametes, called spawn into the water and one or more males release "milt", a white fluid containing many sperm over the unfertilized eggs. Other species of fish are oviparous and have internal fertilization aided by pelvic or anal fins that are modified into an intromittent organ analogous to

1938-517: The creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules . Genitalia 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

1995-437: 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 animals (including humans), the male sex organs include the testicles , epididymides , and penis ; the female sex organs include the clitoris , ovaries , oviducts , and vagina . The testicle in

2052-401: The fallopian tube into the uterus. Hormones produced by the ovaries prepare the uterus to receive the ovum. The ovum will move through her fallopian tubes and awaits the sperm for fertilization to occur. When this does not occur, i.e. no sperm for fertilization, the lining of the uterus, called the endometrium , and unfertilized ova are shed each cycle through the process of menstruation . If

2109-408: The female reproductive tract that make direct contact with male genitalia or male products (sperm, spermatophores ) during or immediately after copulation". It is hard to find a common origin for gonads . However, 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

2166-428: The female's body. Unlike most vertebrates, female birds typically have only one functional ovary and oviduct . As a group, birds, like mammals, are noted for their high level of parental care. Reptiles are almost all sexually dimorphic , and exhibit internal fertilization through the cloaca. Some reptiles lay eggs while others are ovoviviparous (animals that deliver live young). Reproductive organs are found within

2223-438: The females of most mammalian species don't grow permanent mammaries like human females do either. Like humans, most groups of mammals have descended testicles found within a scrotum, however, others have descended testicles that rest on the ventral body wall, and a few groups of mammals, such as elephants, have undescended testicles found deep within their body cavities near their kidneys . The reproductive system of marsupials

2280-691: The human penis. A small portion of fish species are either viviparous or ovoviviparous , and are collectively known as livebearers . Fish gonads are typically pairs of either ovaries or testicles. Most fish are sexually dimorphic but some species are hermaphroditic or unisexual . Invertebrates have an extremely diverse array of reproductive systems, the only commonality may be that they all lay eggs. Also, aside from cephalopods and arthropods , nearly all other invertebrates are hermaphroditic and exhibit external fertilization . All cephalopods are sexually dimorphic and reproduce by laying eggs . Most cephalopods have semi-internal fertilization, in which

2337-684: The male and the ovary in the female are called the primary sex organs . All other sex-related organs are known as secondary sex organs . The outer parts are known as the genitals or external genitalia , visible at birth in both sexes, while the inner parts are referred to as internal genitalia , which in both sexes, are always hidden. 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

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2394-433: The male in one testis or more commonly two, is transmitted to the female during mating by means of external genitalia . The sperm is stored within the female in one or more spermathecae . At the time of fertilization , the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor . Arachnids may have one or two gonads , which are located in

2451-400: The male inserts their erect penis into the female 's vagina and ejaculates semen , which contains sperm . The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum . Upon successful fertilization and implantation, gestation of the fetus then occurs within the female's uterus for approximately nine months, this process

2508-430: The male places his gametes inside the female's mantle cavity or pallial cavity to fertilize the ova found in the female's single ovary . Likewise, male cephalopods have only a single testicle . In the female of most cephalopods the nidamental glands aid in development of the egg. The "penis" in most unshelled male cephalopods ( Coleoidea ) is a long and muscular end of the gonoduct used to transfer spermatophores to

2565-454: The other planarian, giving and receiving sperm. In most plant species, an individual has both male and female sex organs (a hermaphrodite ). 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

2622-485: The ovum is fertilized by sperm, it will attach to the endometrium and embryonic development will begin. Most mammal reproductive systems are similar, however, there are some notable differences between the non-human mammals and humans. For instance, most male mammals have a penis which is stored internally until erect , and most have a penis bone or baculum . Additionally, both males and females of most species do not remain continually sexually fertile as humans do and

2679-526: The periods and countries, facial hair has been prohibited in armies or, on the contrary, an integral part of the uniform. Many religious male figures are recorded to have had facial hair; for example, numerous prophets mentioned in the Abrahamic religions ( Judaism , Christianity and Islam ) were known to grow beards. Sikhism mandates growing beards; in Shia Islam, trimming beards is allowed but shaving them

2736-406: 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). 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

2793-429: The reproductive structures of angiosperms , are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants ( green algae , mosses , liverworts , hornworts , ferns and gymnosperms such as conifers ) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how

2850-506: The rest of the reproductive system, whether internal or external. The Latin term genitalia , sometimes anglicized as genitals , is used to describe the externally visible sex organs. In general zoology , given the great variety in organs, physiologies, and behaviors involved in copulation , male genitalia are more strictly defined as "all male structures that are inserted in the female or that hold her near her gonopore during sperm transfer"; female genitalia are defined as "those parts of

2907-457: 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 raphe . Each organ/body part 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

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2964-417: 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 known as isogametangia. While male and female gametangia are known as heterogametangia, which occurs in the majority of fungi. Facial hair Facial hair is hair grown on the face , usually on the chin, cheeks, and upper lip region. It

3021-423: The sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Fungal reproduction

3078-447: 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. In many other vertebrates , a single posterior orifice (the cloaca ) serves as the only opening for the reproductive, digestive, and urinary tracts (if present) in both sexes. All amphibians , birds, reptiles , some fish, and

3135-399: 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/genitalia include: External Internal External Internal In typical prenatal development , sex organs originate from

3192-431: The uterus and vagina, non-mammal vertebrate groups have an unmodified oviduct leading directly to a cloaca , which is a shared exit-hole for gametes, urine , and feces . Monotremes (i.e. platypus and echidnas ), a group of egg-laying mammals, also lack a uterus, vagina, and vulva, and in that respect have a reproductive system resembling that of a reptile. In domestic canines, sexual maturity (puberty) occurs between

3249-451: The vagina, the vaginal opening, to the uterus; the uterus , which holds the developing fetus; and the ovaries , which produce the female's ova. The breasts are involved during the parenting stage of reproduction, but in most classifications they are not considered to be part of the female reproductive system. The vagina meets the outside at the vulva , which also includes the labia , clitoris and urethra ; during intercourse, this area

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