Heterosexuality

Heterosexuality is the scientific name for sexual attraction and/or sexual behaviour between animals of the opposite characteristic sex, or being straight. It is the fifth element of the classic quinto-modal continuum of sexual orientation, which consists of asexuality, autosexuality, homosexuality, bisexuality, and heterosexuality. Some theorists extend the continuum to include such concepts as "allosexuality", but these have not yet been accepted by the academic community as actual sexual orientations.

Applying this definition to people complicates it, because there are several determinants that may or may not be important for categorization:


 * 1) Chromosonal indicators (XX, XY or unusual variations)
 * 2) Internal reproductive anatomy (immature, mature or "different")
 * 3) Any of the several hormonal indicators
 * 4) External anatomy (commonly breasts & external genitals, but not always)
 * 5) Projected assumptions of sexuality at birth
 * 6) Projected assumptions of sexuality after birth
 * 7) Individually chosen assumptions after birth
 * 8) Assumptions from external appearances and clothing
 * 9) Assumptions from external behaviours (excluding visual appearances)
 * 10) Assumptions from reputation(s)
 * 11) Situational judgements; changing depending on environments, such as companions, clubs, etc.

For most humans, in most of the time of their lifespan, the above factors may correlate very well. After the sexual hormone production changes about the ages of fifty, changes are expected at physiological, sensory, visual, emotional and physical levels. Inexperienced persons however often are mistaken in their judgements on hetero or other sexualities. Note that if one of the animals involved in the sexual attraction and/or behaviour is intersex, or (more rarely) of indeterminable characteristic sex - and particularly if the sexual attraction and/or behaviour involves something other than another animal (e.g., sexual behaviour between an animal and a plant) - the attraction and/or behaviour cannot be classified quadrimodally as heterosexual, homosexual, etc.

The concept of heterosexuality as applied to humans is further complicated by the distinction between sex and gender in humans. Sexual orientation may be based on sex, gender, or some combination of both: for example, some heterosexuals are attracted only to people of the opposite sex, regardless of those people's gender, and others are attracted to people of the opposite gender, even if they are of the same sex.

People who cannot be classified as "male" or "female" -- in terms of either gender or sex -- cannot have any sexual orientation as that concept is currently constructed; thus, their sexual behaviour cannot be heterosexual, homosexual, though certain types of behaviour can always be classified as autosexual.

Sexual impulses in humans are generally thought to be the product of genetic, chemical, behavioural, sometimes other factors that produce an erotic desire that is generally trained to a particular sexual orientation. Human sexual behaviour routinely is not correlated to an individual's actual or declared sexual orientation. Human behaviour may in fact involve emotional, cognitive, social and physical parts of the body, consciously or deliberately often (but not always), so that a clear label of a type of sexuality may be applied.

Heterosexuality is usually contrasted with homosexuality and sometimes bisexuality. Current trends in psychology suggest heterosexuality and homosexuality may exist on a non-modal continuum rather than as discrete entities. Thus, views on heterosexuality are divided among those who hold that heterosexuality is a concrete idea of attraction towards the opposite sex, versus those that hold that heterosexuality is more fluid. Acknowledging that a person's sex and gender can differ also requires a more flexible definition of heterosexuality.

In the animal kingdom, the vast majority of sexual reproduction results from heterosexual coitus between sexually mature partners. However, many modern psychologists hold that sexuality in humans is a larger term than originally thought, encompassing more complex behaviors. Given the tension between the biological definition of heterosexuality and the modern psychological definition of heterosexuality, political and sociological discussions of the subject are often difficult.

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)

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 maleable 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 an ordinary (nontechnical) English word used to describe a heterosexual person, although the term appears to have originally derived from mid-20th century gay slang, 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 non-human animals, is sometimes used as an offensive slur 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