Sex

Sex is the biological trait of a reproducing organism in producing gametes of one of two different sizes or shapes—male or female gametes. Thus, the typical classification for such organisms, their sex, is also known as either male or female. During sexual reproduction, a male and a female gamete fuse to form a zygote, which develops into an offspring that inherits traits from each parent. By convention, organisms that produce smaller gametes (spermatozoa, sperm) are called male, while organisms that produce larger gametes (ova, often called egg cells) are called female. An organism that

thumb|The symbol of the Roman god Mars (mythology)|Mars (god of war) is often used to represent the male sex. It also stands for the planet [[Mars and is the alchemical symbol for iron.]] Male (symbol: ♂) is the sex of an organism that produces, or is organized to produce, the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilisation. A male organism 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

thumb|The symbol of the Roman goddess Venus (mythology)|Venus is used to represent the female sex in biology.

separation of people according to their sex

sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure, reproduction, or both

the sex-specific patterns of inheritance and presentation when a gene mutation is present on a sex chromosome rather than a non-sex chromosome

differences between the spectrum of a number of bodily characteristics and the spectrum of identities that are a social construct

reflex in some mammals

Thrusting motion of the pelvic region

Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa.

thumb|Lobelia siphilitica is an example of a species with a gynodioecious mating system.

Trioecy is a sexual system characterized by the coexistence of males, females, and hermaphrodites. It has been found in both plants and animals. Like androdioecy and gynodioecy, trioecy is a mixed mating systems.