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Hermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.〔(Merriam-Webster Dictionary ) Retrieved 28 June 2011〕 Many taxonomic groups of animals (mostly invertebrates) do not have separate sexes.〔(【引用サイトリンク】 title=hermaphroditism )〕 In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both partners can act as the "female" or "male". For example, the great majority of tunicates, pulmonate snails, opisthobranch snails and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites.
A rough estimate of the number of hermaphroditic animal species is 65,000. Since the estimated total number of animal species is 1.2 million, the percentage of animal species that are hermaphroditic is about 5%. Arthropods are the phylum with the largest number of species. If these are excluded, the species in the remaining approximately 33 phyla are about one-third hermaphroditic. Most hermaphroditic species exhibit some degree of self-fertilization with fractional rates ranging from 0 to 1.0. The distribution of self-fertilization rates among animals is similar to that of plants, suggesting that similar processes are operating to direct the evolution of selfing in animals and plants.〔
Historically, the term ''hermaphrodite'' has also been used to describe ambiguous genitalia and gonadal mosaicism in individuals of gonochoristic species, especially human beings. The word ''intersex'' has come into preferred usage for humans, since the word ''hermaphrodite'' is considered to be misleading and stigmatizing,〔(【引用サイトリンク】url=http://www.isna.org/faq/hermaphrodite )〕 as well as "scientifically specious and clinically problematic".
==Etymology==
The term derives from the , from ,〔(【引用サイトリンク】publisher=Numen: The Latin Lexicon )〕 which derives from Hermaphroditos ( Ἑρμαϕρόδιτος), the son of Hermes and Aphrodite in Greek mythology. According to Ovid, he fused with the nymph Salmacis resulting in one individual possessing physical traits of male and female sexes;〔Ovid, Metamorphoses, Book IV: The story of Hermaphroditus and Salmacis.〕 according to the earlier Diodorus Siculus, he was born with a physical body combining male and female sexes.〔(Diodorus Siculus — Book IV Chapters 1–7 )〕 The word ''hermaphrodite'' entered the English lexicon as early as the late fourteenth century.〔''Oxford English Dictionary'', 1st edn, s.v. ''hermaphrodite, n. and adj.''; (【引用サイトリンク】url=http://www.etymonline.com/index.php?term=hermaphrodite )〕 Alexander ab Alexandro stated, using the term ''hermaphrodite,'' that the people who bore the sexes of both man and woman were regarded by the Athenians and the Romans as monsters, and thrown into the sea at Athens and into the Tiber at Rome.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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