Inquire this question, and you volition probably receive 1 of two responses:

Aye. People cull to be gay. They are making an immoral choice, which government should discourage.

Or

No. Sexual preference is biologically determined. Government should protect gay people from discrimination because homosexuality is an unalterable attribute of their identity.

These two answers have something in common: With both of them, the science conveniently supports the moral decision.

"Being gay is bad. How wonderful it is that nobody has to be gay!"

"Homosexual behavior should be immune to have place. Isn't information technology fantastic that, by an amazing coincidence, there is no way to cease it?"

What if neither answer is correct?

Perhaps sexual preference tin be changed – and people have the correct to engage in gay sex and have homosexual relationships if they cull to practise so. (The fourth choice, that gay people accept no selection simply to exist gay, but should be punished for it anyhow, is morally unthinkable.)

What does scientific discipline tell us well-nigh sexual preference?

Genes

Nosotros know, from many twin and adoption studies, that sexual preference has a genetic component.

A gay human being is more likely than a straight homo to have a (biological) gay brother; lesbians are more than likely than straight women to take gay sisters.

In 1993, a study published in the journal Scientific discipline showed that families with two homosexual brothers were very likely to have certain genetic markers on a region of the X chromosome known as Xq28. This led to media headlines nigh the possibility of the existence of a "gay gene" and discussions near the ideals of aborting a "gay" fetus.

There have also been headlines about an "alcoholism gene", which makes people get alcoholics, and a "warrior gene", which makes people unusually aggressive.

Genes can't control behavior completely, though. Genes regulate the production of amino acids, which combine to form proteins. The existence or absenteeism of a poly peptide can accept an effect on things like booze tolerance or mood.

Affecting something is non the aforementioned equally having complete control over it.

Environs, like genetics, plays an important role in how our behavior develops.

Alcoholism runs in families non just because there is a genetic component to alcoholism, only besides because children acquire how to cope with stress past watching how their parents and their older siblings behave in stressful situations.

If you come from a culture where alcohol consumption is forbidden, it will be hard for you to become an alcoholic, no thing how your body metabolizes booze.

In that location are factors besides a "warrior factor" that contribute to aggression. Children learn to carry aggressively when they witness aggression beingness rewarded.

If you lot grew upwards in a family or as part of a civilization where aggression was non well accepted, yous would be less probable to be ambitious. You would acquire, from an early age, how to command your aggressive tendencies.

Your surround affects your sexual and romantic relationships.

Throughout history, marriages have been influenced by family relations and by economic needs.

People adhere to cultural constraints of monogamy despite being attracted to people other than their spouses.

Your civilization affects your views on homosexuality.

In some societies, homosexuality is accustomed, in others, it is frowned upon but tolerated, in yet others, it is a serious criminal crime, possibly punishable by death.

Male homosexual behavior was expected in ancient Athens. Today, ritual male homosexuality plays an important office in some cultures in New Guinea.

Your upbringing can influence what y'all find desirable and what you find repulsive. Well-nigh Americans would be probably be nauseated if they learned that, when they thought they had been eating beef, they were, in fact, eating dog, fifty-fifty though there is nothing inherently unhealthy about domestic dog meat.

What you have learned well-nigh homosexuality every bit you were growing upwards will bear on whether yous consider engaging in homosexual acts to exist desirable or icky.

Some people might contend that if you are "genetically gay" just the thought of homosexuality nauseates you, and then you lot but haven't accepted the fact that you really are gay. That statement is based on the assumption that sexual preference is purely biological; therefore, information technology has no place in a discussion nigh the possible causes of homosexuality.

The Encephalon

The structure of the brain might influence sexual preference.

In 1991, a study published in the journal Science seemed to show that the hypothalamus, which controls the release of sex hormones from the pituitary gland, in gay men differs from the hypothalamus in directly men. The third interstitial nucleus of the anterior hypothalamus (INAH3) was constitute to exist more than than twice as large in heterosexual men as in homosexual men

This study was criticized because it used encephalon tissue obtained at autopsies, and all of the homosexual subjects in the study were believed to have died of AIDS.

A later study, which was performed in 2001, showed that HIV status has no significant effect on the INAH3. This study, which also used brain tissue from autopsies, did non reveal any significant deviation between the size of the INAH3 in gay men and straight men. It did, however, show that in gay men, neurons in the INAH3 are packed more closely together than in straight men.

PET and MRI studies performed in 2008 have shown that the two halves of the encephalon are more than symmetrical in homosexual men and heterosexual women than in heterosexual men and homosexual women. These studies have also revealed that connections in the amygdalas of gay men resemble those of straight women; in gay women, connections in the amygdala resemble those of straight men. The amygdala has many receptors for sex hormones and is associated with the processing of emotions.

Some studies have shown that the corpus callosum – the main connexion betwixt the two halves of the encephalon- has a different structure in gay men than in straight men. However, other studies have found no difference.

Gay women and gay men are more probable to be left-handed or ambidextrous than straight women and straight men, co-ordinate to a number of different studies. Some researchers take suggested that this difference in handedness – preference for i paw over the other can be observed in fetuses - is related to differences in the corpus callosum.

A 1992 study showed that the anterior commissure, a smaller connectedness between the brain's 2 hemispheres, is larger in homosexual men than in directly men. Notwithstanding, according to a study that was performed x years later, the size of the anterior commissure is non afflicted by sexual orientation.

We know from studying rats that exposure to sexual practice hormones in the womb during a disquisitional menstruum in brain development affects hereafter sexual orientation. By manipulating hormone levels during this time, scientists can make rats appoint in homosexual behavior later on.

So your encephalon was influencing your sexual preference even before you were built-in.

This can explain why many gay people feel that they have e'er been gay.

Brain development does non stop at nativity, though.

A large amount of brain development takes place during childhood, when you are learning many new things – including how your family and the adults around y'all believe you should feel near things and what they believe is acceptable behavior.

The education you receive equally a child strongly affects how your brain volition develop as you lot grow. For example, children who are given musical training experience changes to areas of the brain associated with hearing and motor control.

With the right experiences, your brain tin change even afterwards you have reached adulthood.

Both London taxi drivers and professional piano tuners show increases in grey thing in areas of the brain associated with the skills needed for their professions. The size of the increase in grayness matter correlates with the numbers of years of experience.

In one experiment, elderly subjects showed increases in gray matter in certain parts of their brains after they were taught to juggle.

With proper rehabilitation, people who take suffered brain damage from strokes can develop new neural connections and regain some of their erstwhile skills.

It'southward important to point out that the regions of the encephalon that accept been shown to change because of training and experience are not the parts of the brain that take been associated with sexual preference.

However, women exercise experience changes to the structure of the hypothalamus – which is thought to be associated with sexual orientation - throughout the menstrual cycle.

So far, attempts to "cure" homosexuality by operating on the brain – homosexuals were once given lobotomies - have never worked.

(Attempts to eliminate homosexuality via hormone therapy oasis't been effective either. While changes in hormone levels in the womb during a very specific time can have an event on future sexual preference, hormone levels have no effect on sexual preference after. Gay men and straight men take the aforementioned levels of sexual practice hormones; sex activity hormone levels are the same in gay women and straight women.)

Today, however, we know much more about the brain than we did when homosexuality was considered a illness that required treatment, and the amount of knowledge that we have about the brain is increasing.

Perhaps 1 day we volition exist able to conform sexual preference via surgery - focusing on the item regions of the brain that are associated with sexual preference – or via neural implants or training.

If Sexual Preference Can Be Changed

Fifty-fifty if gay people can never stop being attracted to members of the same sex, they can acquire not to human action on their desires.

People already larn to stop smoking, to give up sure foods, and not cheat on their husbands or wives.

If nosotros ascertain being gay as engaging in homosexual beliefs (the concept of "gay" as an identity is a Western cultural concept – people who have sex with both men and women may call themselves gay, direct or bisexual, depending on the rules of their culture or subculture), then people finish being gay as soon as they stop engaging in this behavior.

Should they end?

If they could, should they change their brains (or have their brains changed) in order to make themselves straight?

I believe that people have the right to engage in whatever behavior that they choose, equally long as their deportment practice not harm others, and I believe that gay sexual practice and gay relationships do non cause harm to anyone. Therefore, people who are gay past choice have the correct to remain that way

(Of course, there are abusive and unhealthy gay relationships that should not exist tolerated, merely as there are unhealthy heterosexual relationships that should not be tolerated.)

If sexual preference tin can be altered, and so people who support gay rights can't rely on the argument that gay people should be protected from discrimination because gay people accept no choice merely to be gay – an argument that seems similar an amends for homosexuality, as if homosexuality is a disease for which in that location is no cure.

At that place is an chemical element of homophobia in that argument– the implication that gay people would become straight, if only they could. Supporting gay spousal relationship becomes equivalent to supporting the construction of wheelchair ramps. The "gays can't help being that manner" arroyo is reminiscent of the old view of homosexuality as a psychiatric illness.

In a weblog mail for Slate, J. Bryan Lowder comments on Cynthia Nixon's claim that her lesbianism is a choice. Lowder agrees with Nixon that blaming biology "cedes a great deal of control to bigoted people."

You don't have to defend a controversial activity by arguing that you have no control over your behavior. In fact, when we you practise then, you reinforce the belief that your beliefs is undesirable.

Nobody has to testify that biology forces them to vote for a particular party, exercise a certain organized religion or follow a item diet.

Just every bit gay people who are happy as they are should not exist forced to change their sexual orientation, gay people who want to be straight should have the right to modify if they can – and the correct give-and-take is "change" – non "cure".

In his blog postal service, Lowder states, "Many critics will argue that appealing to biology is the just manner to protect against the attacks of the religious right."

It might brand these critics unhappy to hear this, but that's not how scientific discipline works.

Science doesn't change in order to support political opinions.

Scientific beliefs change equally we gain new information, and sometimes science tells us things that we would rather not hear.

Get used to it.

References:

Bailey, J.Yard. & Pillard, R.C. (1991). A genetic study of male person sexual orientation. Archives of Full general Psychiatry, 48(12): 1089–1096.

Balthazart, J. (2012). Brain development and sexual orientation. Colloquium Series on the Developing Brain, Morgan & Claypool Publishers.

Baroncini, M. et al. (2010). Sex steroid hormones-related structural plasticity in the homo hypothalamus, NeuroImage, fifty(2): 428-43.

Boyke, J., Driemeyer, J., Gaser, C., Büchel, C. & May, A. (2008). Training induced encephalon structure changes in the elderly. Periodical of Neuroscience, 28(28): 7031-7035.

Burri, A., Cherkas, L., Spector, T. & Rahman, Q. (2011). Genetic and environmental influences on female person sexual orientation, childhood gender typicality and adult gender identity, PLOS Ane 6(7): e21982.

Hamer, D.H., Hu, Due south., Magnuson, V.L., Hu, N. & Pattatucci, A.M. (1993). A linkage between Deoxyribonucleic acid markers on the X chromosome and male sexual orientation. Science, 261(5119): 321-327.

Hyde, G.L. et al. (2009). The effects of musical training on structural brain development: a longitudinal study. Annals of the New York Academy of Sciences, 1169: 182-186.

Johannson, B.B. (2011). Current trends in stroke rehabilitation: A review with focus on brain plasticity. Acta Neurologica Scandinavica, 123(iii): 147-159.

LeVay, S. (1991). A difference in hypothalamic structure between heterosexual and homosexual men. Science, 253(5023): 1034-1037.

Maguire, East.A. et al. (2000). Navigational-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences Usa, 97(8): 4398–4403.

Prinz, J. (2012). Beyond homo nature: how culture and experience shape our lives New York: Penguin Group Us.

Teki, S. et al. (2012). Navigating the auditory scene: an expert role for the hippocampus. Journal of Neuroscience, 32(35): 12251-12257.

Whitam, F.L., Diamond, M. & Martin J. (1993). Homosexual orientation in twins: A written report on 61 pairs and three triplet sets. Archives of Sexual Behavior, 22(three): 187-206.

Photograph credits: Vancouver Gay Pride Parade 2008 by ecodallaluna on Wikimedia Commons; Deoxyribonucleic acid by ynse on Wikimedia Commons; Brain fMRI by NASA.