Heterosexual

Heterosexuality primarily refers to aesthetic, sexual, and romantic attraction exclusively between two individuals of opposite genders. It is characterised as a sexual orientation, contrasted with homosexuality and bisexuality.

Etymology
Hetero- comes from the Greek word heteros, meaning "different" (for other uses, see heterozygote, heterogeneous), and the Latin for sex (that is, characteristic sex or sexual differentiation). The term "heterosexual" was coined shortly after and opposite to the word "homosexual" by Karl Maria Kertbeny in 1868 and was first published in 1869. [2] "Heterosexual" was first listed in Merriam-Websters's New International Dictionary as a medical term for "morbid sexual passion for one of the opposite sex", but in 1934 in their Second Edition Unabridged it is a "manifestation of sexual passion for one of the opposite sex; normal sexuality". (Katz, 1995)

Humans
Heterosexuality, like any forms of identity is very subjective. In western society, one is generally thought of as heterosexual if one derives either all, or the vast majority of their erotic and/or sexual stimulation from people of the different sex to them. In other cultures a heterosexual man may engage in homosexual intercourse provided that he keeps the role traditionally assigned to his sex during intercourse and his gender during the surrounding relationship. Also, in some cultures a heterosexually identifying man may assume any role during homosexual congress as a social action provided he maintain a relationship with a woman in his family life. Cultural allowances such as this have been historically rarer amongst women, but more recently have been tolerated more than the male equivalents largely because of its connection to some schools of feminism.

Definitions of sexuality tends to be narrower to most heterosexuals than it is to people of other sexual orientations. In most cases a potential partner's sex is determined wholly by anatomic sex at birth and genetic sex. Many heterosexuals would argue that one whose determination of a partner's sex deviates from that criterion cannot truly be heterosexual. Transgendered people and even those with many natural intersex conditions are very rarely seen as potential mates by heterosexuals, even those who consider themselves tolerant and accepting to such identities.

Animals
In the animal kingdom, the vast majority of sexual reproduction results from heterosexual coitus between sexually mature partners.

History and demographics
The prevalence of exclusive heterosexuality has varied over the centuries and also from culture to culture. See Demographics of sexual orientation

Though there have always been individuals (sometimes in a majority, sometimes in a minority) who were exclusively attracted to those of the opposite sex, heterosexuality as an identity (just like homosexuality) has developed only since the middle of the nineteenth century.

The history of heterosexuality is part of the history of sexuality. That history and science derivative of it is far from complete. Owing to complications of human politics and prejudice, coupled with the malleable nature of human behaviour, it will be some time before the history and nature of all forms of human sexual behaviour are truly known.

Psychological factors relating to sexuality
Main article: Sexual orientation

A broad array of opinion holds that much human behavior ultimately is explainable in terms of natural selection. From this point of view, the shifting social balance between heterosexual and homosexual desire has evolved as a fitter survival strategy for the species than either an exclusively heterosexual or homosexual configuration of desire.

In traditional societies individuals are often under heavy social pressure to marry and have children, irrespective of their sexual orientation. In modern society, many homosexual people who wish to have children have found a way to satisfy their nurturing instincts, either through fostering or adopting children, or through artificial or natural insemination.

Not all people who are attracted to, or have sexual relationships with members of the opposite sex identify themselves as heterosexual: people who do not identify primarily as heterosexual may sometimes engage in heterosexual behaviour. Similarly, some people frequently have sex with members of the same sex yet still see themselves as heterosexual. (See bisexuality)

According to American Psychiatric Association (APA), there are numerous theories about the origins of a person's sexual orientation, but some believe that "sexual orientation is most likely the result of a complex interaction of environmental, cognitive and biological factors", and that genetic factors play a "significant role" in determining a person's sexuality. [5] The APA currently officially states that sexual orientation is not chosen and cannot be changed, a radical reversal from the recent past, when non-normative sexuality was considered a deviancy or mental ailment treatable through institutionalization or other radical means.

Slang
The term "straight" is a mid-20th century gay slang term for heterosexuals, ultimately coming from the phrase "to go straight" (as in "straight and narrow"), or stop being gay [3]. One of the first uses of the word in this way was in 1941 by author G. W. Henry. Henry's book concerned conversations with homosexual males and used this term in connection with the reference to ex-gays. Though not originally intended to refer to heterosexuals, like the meanings of many words, its primary usage has changed over time.

The term breeder, a word which is normally applied to animals, is sometimes used to describe heterosexuals.

Books

 * Kinsey, Alfred C., et al., "Sexual Behavior in the Human Male". Indiana University Press. ISBN 0253334128
 * Kinsey, Alfred C., et al., "Sexual Behavior in the Human Female". Indiana University Press. ISBN 025333411X
 * Musser, Trevor J., a well known heterosexual wrote "Loving women". Ohio University Press. ISBN 12243637134