The causes of sexual orientation have been the subject of much attention and research in recent years. Usually, research on sexual orientation is focused on causes of homosexuality. This is largely because heterosexuality has traditionally been considered "normal" and homosexuality an aberration, although this view has been contested and weakened by the results of the research as well as by political activism.

There has also been a realization that any attempt at understanding the causes of sexual attraction to the other or the same sex will be more successful if we understand the mechanisms that underlie sexual attraction per se, and more specifically what causes many people to feel sexual attraction primarily towards members of one particular sex.

"Normal" orientation

While heterosexuality is considered the statistical or biological norm, the concept of "normal" and "abnormal" with its connotations of sickness or moral judgment are no longer considered valid by most researchers outside of those whose religious (or other) beliefs include such a judgment.

Even the belief that heterosexuality is the statistical norm has been challenged by some researchers, starting with Alfred C. Kinsey, who claimed that most people's orientation falls along a gradual scale between the two extremes of heterosexuality and homosexuality, with society influencing people to choose socio-normal sexual outlets. Opponents of Kinsey have claimed that his research methods were not objective (see Kinsey Reports).

Some early civilizations, such as those of ancient Greece and Rome, often accepted homosexual behavior but, in general, did not make a distinction between homosexuality and heterosexuality as orientations. Homosexual and heterosexual responses were considered to both be "natural" feelings that manifest to a greater or lesser degree in different individuals. The Greek civilization in particular considered it quite natural for young men to have older mentors with whom sexual interaction was accepted. A similar example was reported in Rome too, with the well known "Satyricon" by Petronius Arbiter, in which a common acceptance of pedophilia is also described. There was no serious inquiry into the causes of sexual orientation, because there was relatively little awareness of it as a concept; people were free to follow their personal inclinations.

The traditional view that homosexuality was due to man's rebellious or fallen nature, or demonic temptation has given way to scientific explanations which regard homosexuality as natural. Scientists are now questioning the view that homosexuality is a freely made choice or "lifestyle" that one has decided to follow, and many religions are updating their theologies to conform with science.

Research

The last 20 years have seen an explosion in scientific research into the genetic, biological and psychological causes of homosexuality. Most research looks at human sexuality, but homosexual behavior has been observed in non-human animals as well as in humans.

Each of the following factors has been proposed as a possible contributor to one's sexual orientation. Various people accept one or a combination of these factors. The majority of researchers in the field believe orientation is probably determined not by any one single factor but by some combination of them, except that nearly all researchers reject conscious choice as a factor. Choice is believed to affect whether one externalizes one's orientation, but is not believed to be a factor in determining the orientation.

Biological Factors

Research, and the experience of non-heterosexuals, suggests that sexual orientation is set in early childhood and perhaps in some individuals even earlier. Studies of homosexual identical twins suggest that when one twin is homosexual that there is a 40 to 60 percent chance that the other twin will also be homosexual. In fraternal twins the figure is 15 to 30 percent. For same sex non-twin siblings the figure is 5 to 10 percent, or roughly the background level (ranges are from a combination of [1] & [1]).

For many, these data strongly indicate a significant biological influence on sexual orientation. For many others, including two of the three authors (Bailey and Pollard) of the studies cited above, there is a worry that recruiting subjects from readers of gay advocacy magazines may have skewed the results.

Genetic Biological Factors

Despite much speculation on genetic variations that could lead to homosexuality, it is unknown whether and to what extent any one's genes could compel the development of homosexuality.

Some popular reports on research, published in a Newsweek cover article entitled "Gay Gene?" had suggested that there was a genetic basis for homosexuality which make people more likely to become homosexual. These reports were later repudiated by the researchers, who said that their work had been misconstrued, and Newsweek printed a retraction on an inside page.

Non-Genetic Biological Factors

Many other biological factors might be involved. The following topics need to be elucidated in this entry, with references to important scientific and medical journal articles, and books which summarize said articles.

Some research has also looked at non-genetic biological factors such as hormonal factors and the development of the foetus within the womb.

Psychological and Sociological Factors

Richard Cohen of the International Healing Foundation claims to have found a constellation of causal factors, primarily non-genetic.

Some other researchers have surveyed homosexuals to learn how social and psychological influences might have affected their sexual orientation.

In surveys of gay men and lesbians, the majority assert that they were born that way. Most of them report that they knew they were "different" from an early age, often by puberty and not uncommonly in prepubescence. Instances of individuals stating that they chose to be gay are extremely rare. This and other anecdotal evidence gives little concrete proof either way, but it is considered by many to be strongly indicative of the likelihood that orientation is not a choice. See Nature versus nurture debates.

Conscious Choice

Some people, primarily Christians and most often fundamentalists, advocate the view that people's sexual orientation follows from their behavior: e.g., if they try homosexual acts, they might like them and thereby acquire a homosexual orientation. In fact some also believe that a heterosexual orientation is formed in the same way, and that the only genetic element is in the basic underlying sexual desire. Some people who share this view operate prayer ministries and 12-step programs to help people change from homosexuality to heterosexuality.

There is no independent research that validates the views or methods of these advocates.

See also