A male (♂) organism is the physiological sex that produces sperm.
Each spermatozoon can fuse with a larger female gamete, or ovum, in
the process of fertilization. A male cannot reproduce sexually without
access to at least one ovum from a female, but some organisms can
reproduce both sexually and asexually. Most male mammals, including
male humans, have a Y chromosome, which codes for the production of
larger amounts of testosterone to develop male reproductive organs.
Not all species share a common sex-determination system. In most
animals, including humans, sex is determined genetically, but in some
species it can be determined due to social, environmental, or other
factors. For example,
Cymothoa exigua changes sex depending on the
number of females present in the vicinity.
3.1 Genetic determination
3.2 Environmental determination
4 Secondary sex characteristics
5 See also
The existence of two sexes seems to have been selected independently
across different evolutionary lineages (see convergent evolution). The
repeated pattern is sexual reproduction in isogamous species with two
or more mating types with gametes of identical form and behavior (but
different at the molecular level) to anisogamous species with gametes
of male and female types to oogamous species in which the female
gamete is very much larger than the male and has no ability to move.
There is a good argument that this pattern was driven by the physical
constraints on the mechanisms by which two gametes get together as
required for sexual reproduction.
Accordingly, sex is defined operationally across species by the type
of gametes produced (i.e.: spermatozoa vs. ova) and differences
between males and females in one lineage are not always predictive of
differences in another.
Male/female dimorphism between organisms or reproductive organs of
different sexes is not limited to animals; male gametes are produced
by chytrids, diatoms and land plants, among others. In land plants,
female and male designate not only the female and male
gamete-producing organisms and structures but also the structures of
the sporophytes that give rise to male and female plants. As of the
year 2012, the
United Arab Emirates
United Arab Emirates has the highest ratio of human
males in the world, followed by Qatar.
A common symbol used to represent the male sex is the
Mars symbol, ♂
(Unicode: U+2642 Alt codes: Alt+11)—a circle with an arrow pointing
northeast. The symbol is identical to the planetary symbol of Mars. It
was first used to denote sex by
Carl Linnaeus in 1751. The symbol is
often called a stylized representation of the Roman god Mars' shield
and spear. According to Stearn, however, all the historical evidence
favours that it is derived from θρ, the contraction of the Greek
name for the planet Mars, which is Thouros.
Main article: Sex-determination system
Photograph of an adult male human, with an adult female for
comparison. Note that both models have partially shaved body hair.
The sex of a particular organism may be determined by a number of
factors. These may be genetic or environmental, or may naturally
change during the course of an organism's life. Although most species
with male and female sexes have individuals that are either male or
female, hermaphroditic animals, such as worms, have both male and
female reproductive organs.
Most mammals, including humans, are genetically determined as such by
XY sex-determination system
XY sex-determination system where males have an XY (as opposed to
XX) sex chromosome. It is also possible in a variety of species,
including humans, to be XXY or have other intersex/hermaphroditic
qualities, though one would still be considered genotypically (if not
necessarily phenotypically) male so long as one has a Y-chromosome.
During reproduction, a male can give either an X sperm or a Y sperm,
while a female can only give an X egg. A Y sperm and an X egg produce
a male, while an X sperm and an X egg produce a female.
The part of the Y-chromosome which is responsible for maleness is the
sex-determining region of the Y-chromosome, the SRY. The
Sox9, which forms feedforward loops with
PGD2 in the gonads,
allowing the levels of these genes to stay high enough in order to
cause male development; for example, Fgf9 is responsible for
development of the spermatic cords and the multiplication of Sertoli
cells, both of which are crucial to male sexual development.
The ZW sex-determination system, where males have a ZZ (as opposed to
ZW) sex chromosome may be found in birds and some insects (mostly
butterflies and moths) and other organisms. Members of the insect
order Hymenoptera, such as ants and bees, are often determined by
haplodiploidy, where most males are haploid and females and some
sterile males are diploid.
In some species of reptiles, such as alligators, sex is determined by
the temperature at which the egg is incubated. Other species, such as
some snails, practice sex change: adults start out male, then become
female. In tropical clown fish, the dominant individual in a group
becomes female while the other ones are male.
In some arthropods, sex is determined by infection. Bacteria of the
Wolbachia alter their sexuality; some species consist entirely
of ZZ individuals, with sex determined by the presence of
Secondary sex characteristics
Main article: Secondary sex characteristic
In those species with two sexes, males may differ from females in ways
other than the production of spermatozoa. In many insects and fish,
the male is smaller than the female. In seed plants, which exhibit
alternation of generations, the female and male parts are both
included within the sporophyte sex organ of a single organism. In
mammals, including humans, males are typically larger than females. In
birds, the male often exhibits a colorful plumage that attracts
Look up male in Wiktionary, the free dictionary.
Wikimedia Commons has media related to males.
^ Creighton, Jolene. "Meet The Sex-Changing, Tongue-Eating Parasite:".
From Quarks to Quasars. Retrieved 7 April 2014.
^ Dusenbery, David B. (2009). Living at Micro Scale, Chapter 20.
Harvard University Press, Cambridge, Mass.
Gender Statistics Highlights from 2012 World Development Report".
World DataBank, a compilation of databases by the World Bank. February
^ The Origin of the
Female Symbols of Biology, William T.
Stearn, Taxon, Vol. 11, No. 4 (May, 1962), pp. 109-113
^ Moniot, Brigitte; Declosmenil, Faustine; Barrionuevo, Francisco;
Scherer, Gerd; Aritake, Kosuke; Malki, Safia; Marzi, Laetitia;
Cohen-Solal, Ann; Georg, Ina; Klattig, Jürgen; Englert, Christoph;
Kim, Yuna; Capel, Blanche; Eguchi, Naomi; Urade, Yoshihiro;
Boizet-Bonhoure, Brigitte; Poulat, Francis (2009). "The
independently of FGF9, amplifies SOX9 activity in Sertoli cells during
male sexual differentiation". Development. 136 (11): 1813–1821.
doi:10.1242/dev.032631. PMID 19429785.
^ Kim, Y.; Kobayashi, A.; Sekido, R.; Dinapoli, L.; Brennan, J.;
Chaboissier, M. C.; Poulat, F.; Behringer, R. R.; Lovell-Badge, R.;
Capel, B. (2006). "Fgf9 and Wnt4 Act as Antagonistic Signals to
Sex Determination". PLoS Biology. 4 (6): e187.
doi:10.1371/journal.pbio.0040187. PMC 1463023 .
Evolution of sexual reproduction
Sexual reproduction in animals
Gender and sexual identities
Ambiphilia, Androphilia, Gynephilia
Attraction to transgender people
Same gender loving
Disorders of sex development
Ego-dystonic sexual orientation
Erotic target location error
Human female sexuality
Human male sexuality
Sex and gender distinction
Sex reassignment surgery
Sexuality and gender identity-based cultures
Social construction of gender
The NeuroGenderings Network
Violence against women
Violence against women and men (gendercide)
Gender studies portal