Male (♂) refers to the sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. 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.

Not all species share a common sex-determination system. In humans and most animals, sex is determined genetically but in other species it can be determined due to social, environmental, or other factors. The existence of two sexes seems to have been selected independently across different evolutionary lineages (see Convergent Evolution). Accordingly, sex is defined operationally across species by the type of gametes produced (ie: 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.

Anatomy

All males, regardless of independent origin, kingdom, or other phylogenetic subdivision, share at least the anatomy to produce male gametes. Some have sophisticated organs and organ systems designed to produce, dispense, and deliver the gamete to a location suitable for ovum fertilization.

Even where structures and cell types have arisen independently, "sperm" is ordinarily used to refer to the male gamete. Among animals that undergo internal fertilization, "penis" is often used to refer to an organ inserted into the female for insemination. This process is called sexual intercourseFact: date=July 2008.

Symbol

A common symbol used to represent the male gender is the Mars symbol, ♂ (Unicode: U+2642 Alt codes: Alt+11)—a circle with an arrow pointing northeast. This is often called a stylized representation of the Roman god Mars' shield and spear Fact: date=July 2008.

Sex determination

main: Sex-determination system

The sex of 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.

Genetic determination

Most mammals, including humans, are genetically determined as such by the 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 human beings, to be XXY or have other intersex/hermaphroditic qualities. These qualities are widely reported to be as common as redheadedness (about 2% of the population). 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 boy, while an X sperm and an X egg produce a girl. 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 Hymenoptera, such as ants and bees, are determined by haplodiploidy, where most males are haploid and females and some sterile males are diploid.