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Nature versus Nurture: Homosexuality's Link to Biology and Society

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Biology 202, Spring 2005
Third Web Papers
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Nature versus Nurture: Homosexuality's Link to Biology and Society

Sonya Safro

The New York Aquarium in Coney Island, Brooklyn, has recently confirmed two of their penguins to be gay. Wendell and Cass, who refused to separate from one another when zookeepers attempted to increase breeding by force, are now known as the best couple among all the penguins at the aquarium. Penguins do not have external organs, so the zookeepers did not know that Wendell and Cass were both male for a long time before they finally took a look. Another pair of gay penguins, Silo and Roy, have even adopted an egg together; in fact, they did a great job raising the chick. Homosexuality has been documented in more than 450 animal species: flamingos, owls, bears, monkeys, and even fish to name a few. The world has proven to be full of homosexual creatures1.

I first came across this article when a friend of mine and I were having a long conversation about homosexuality and biology. I had believed that there was an evolutionary objection to any genetic theories of homosexuality: animals are programmed to reproduce and that is their natural motive for having sex. However, my friend informed me about the penguins, and I began to think more about whether homosexuality is a trait that is inherited at birth, or whether sexual orientation is dependent on the environment one is brought up in. I wish to explore the "gay gene" theory, the debate over nature versus nurture, and the emotional, political, and social controversies about homosexuality.

In 1993 Dean Hamer, a scientist who works at the National Cancer Institute, wrote an article in the journal Science called "A Linkage Between DNA Markers on the X Chromosome and Male Sexual Orientation.2 This controversial article explored homosexuality from a scientific perspective: it was not a choice, or a "form of psychological deviance," but more about biology and genetics. Politics hit the roof with this article. The gene debate and supporters of a biological cause for homosexuality are linked with being pro-gay, just as those who claim science has nothing to do with it may be targeted as homophobic. It's important to wonder: could researchers be taking a stance based on their own sexual orientation?

Hamer claimed to have found evidence for an unidentified gene on the X-chromosome that was passed from mother to son and had an influence on the child becoming gay. With research about gay brothers, Hamer and his colleagues assert that the Mothers' genetic skew correlates to their gay sons. Hamer is trying to discover a gene through the X-chromosome and find out how it controls the sexual orientation trait. On the other hand, this has been challenged by other scientists who believe that Hamer's evidence and research is too weak and broad. It appears as though many other factors may be influencing each of the mothers' sons, and that a more varied and repetitive research is needed.

This unidentified gene has also been found in fruit flies. However, the leap from flies to humans has caused many biologists and researchers to claim that homosexuality is resolutely embedded in genetics and biology. In other words, even if we cannot fully identify the gene at this moment, or completely understand how this is so, biology is the main factor. Finding same sex behavior and the unidentified gene in flies, as well as mice, sheep, and other animals is important because humans share the bulk of their DNA with these other species3.

A gay sheep study backs up the notion that biology has a lot to do with homosexuality. The hypothalamus is known to control sex hormone release as well as sexual behavior, has been found to have distinctive differentiation in the rams. The hypothalamus is twice as large in rams as in ewes, however in gay rams; it was the same size as the "straight" females. These differences in the hypothalamus in size are almost identical to the differences found in neuroscientist Simon LeVay's study of the brains of gay men. Sheep and humans are the only animals where males can physically express utterly gay sexual preferences. Also, the hypothalamus has an enzyme called aromatase, which converts testosterone into estrogen. This has a lot to do with the hormones that present during a fetus' development.

A very interesting debate regarding homosexuality is this "nature vs. nurture" argument. Thomas Schmidt, in "Straight & Narrow? Compassion and Clarity in the Homosexual Debate," takes a religious stance, and looks at homosexuality through something he calls the "multiple-variant model.4" This model is Schmidt's attempt to get rid of the biological theory that homosexuals were born that way, which he believes is not correct. This multiple-variant model associates many external, environmental factors with a person's sexual orientation. Social constructivism, early childhood environment, early trauma, and individual choice are the most critical factors Schmidt connects to homosexuality.

Schmidt argues that the way a parent fosters his or her child influences a child's eventual sexual preference. He gives many examples of external factors, such as a son who doesn't receive love from his father, thus always searches to fulfill this emptiness by engaging in relationships with other men. If a child, more specifically a boy, is teased all throughout his childhood by his peers and considered a "sissy," then he will relate more to the girls in his age group and become like one of them, ultimately even liking males.

Schmidt also talks about choices. Feminism, he claims, is a big influence on a female becoming attracted to someone of the same sex, as well as people considered to be counter-culture like. Basically, Schmidt believes that homosexuality is a choice, and furthermore a morally wrong one that is only perpetuated by people's decisions to act upon it. He ends his argument by suggesting Christian therapy to help stop homosexuality.

This argument gives of a religious fanatic vibe. While Schmidt makes some useful points about the need to replicate biological researches and evidence of its link to homosexuality, and while I do believe sexual orientation has lots to do with environmental factors, his message is biased and conservative: based on his religious upbringings, he has learned that homosexuality is a sin, and that gays choose to commit this "sin." Schmidt claims that no relevant or important research has been done to actually prove a genetic association to homosexuality, thus he dispels all notions of the likelihood. However, in truly understanding homosexuality and dealing with this highly controversial and emotional topic, I believe that people should be open and willing to all possibilities.

A friend of mine at Bryn Mawr College, who identifies herself as a lesbian, told me that she can't help being gay: "I knew since I was 10 that I liked girls. I tried to keep it a secret but I just couldn't hide it or change the way I was. It's not fun being gay, I know lots of people who wish they weren't." As I contemplated my friend's statement, I thought about how society is so devoted to and affected by the "gay gene" debate and the issue of homosexuality as either genetically influenced or environmentally caused.

Why indeed are researchers attempting to find a gene that proves once and for all that homosexuality is in fact not a choice but a hereditary feature? Could this lead to homosexuality being considered a flaw and something that may be "fixed?" Why can't we live in a world where it's simply okay for a person to be gay, or straight? So many theories have been given concerning love and the brain, such as love being simply a chemical reaction stimulated in the brain causing someone to feel that they are truly in love with another. However, the world is still full of romantics who will always believe that love is an amazing, unexplainable thing. Homosexuality, unlike love, is not regarded as natural or even unexplainable by many people.

So is homosexuality an instinct people are born with, or is it learned? Or both? I have come to learn more about biology and homosexuality, the current research that has been going on and that has been debated. I think research is important in understanding why we are who we are. It is pressing, however, to see that homosexuality is such a heated topic. It is scary to think that our last presidential election results actually had so much to do with gay rights. People are set in their beliefs, whether cultural or religious, and while environment of course plays a huge role in people becoming who they are, perhaps we need to look outside of just society's influence.

If we accept that homosexuality is indeed biologically inherited and not an option, then it appears that many people will have to accept this as unalterably and unchangeably part of that person. Homosexuals would have to be accepted, because then it would be clearly wrong to discriminate, as it goes for race and gender5. Still, there may be repercussions with the acceptance of the "gay gene" theory, such as continued discrimination by others now viewing homosexuality as a defect. Our society is a complex one, where science and biology has so much to do with facts, reality, and our further development as intelligent human beings in a civilized world. Yet, we continue to hold prejudices, set beliefs and views in a culture-driven humankind that still has a lot of learning, and a lot of "getting it less wrong."

1 Columbia news Science
2 Http:// The "Gay Gene" Debate
3 Http:// The Gene Debate
4 Http:// "Straight & Narrow? Compassion and Clarity in the Homosexual Debate
5 Accepting Homosexuality


Comments made prior to 2007
Let's, for the sake of argument, say that there is a homosexual 'gene'. People who were gay would of course not be faulted for who they are. I believe it's when homosexuality is pursued that it becomes a sin in many eyes. What if we're born with an 'aggressive' gene? Should the aggressive actions of this individual be condoned because, "it's who they are"? Why do some out of the closet homosexuals (Anne Heche)currently have boyfriends? Or is there a 'bi-sexual' gene too??? Perhaps this was a CHOICE she made?! I don't know. I think what the majority of Americans are tired of is the pushing of acceptance. We know homosexuality exists already.....Enough. It's everywhere you turn. Movies, sitcoms, commercials, books. I'm not going to condemn anyone who is gay, but I'm also never going to accept their lifestyle. Stop Pushing It!!! ... John Cruisman, 7 October 2007


Guest's picture


I'm a teenager in high school who is a homosexual. I have tried many times to change my sexuality through religous, social, and psychiatric means however am completely unable too. I am a strict christian yet my own beliefs condemn me to hell. I wish I sould change who I am eveyday but it's still who I am. I have no choice but to accept the fact that regardless of Nature or Nurture, it can't be changed. Those who criticize homosexuals: I am not telling you to change your beliefs, but I'm asking you to accept the fact that we homosexuals are here and cannot be changed through God or psychotherapy.

Serendip Visitor's picture

It can't be changed. What if I held the key?

You make a good argument that in the end you can't change. But let's assume it was a roll of the dice and you are gay. We could roll the dice again, but would you really want me to do that? I could ask the same of straight people.

Mimi's picture

Homosexuality is a disorder

Homosexuality is a disorder and no referendum can change this fact. In 1973 homosexuality was removed by APA from list of mental diseases following referendum and protests of gay lobby. How credible can any organization be if decides on facts by voting?? Homosexual people in fact dont have any mental disorder apart from pathological sexual orientation. Therefore homosexuality leads to disturbance in the basic organism's function which is procreation.
The fact that homosexuality is also amongst animals doest make it proper behaviour. So is cannibalism, cancer and other abnormalities.

Serendip Visitor's picture

Actually, Cancer is not a

Actually, Cancer is not a behavior. And I question you. Do you know the meaning of life? Does anyone?

Serendip Visitor's picture

Grow up

Everyone needs to grow up because nothing is going to change, there a lot of people that are gay/lesbian/bisexuals in the world that they are still in the closet. They are to afraid to come out because of what society puts into to other peoples heads. I doing a paper for english class and gays/lesbians are not treated with the right kind of respect and they are limited. Dont judge people are there sexual orietation and just accpeting it or atleast tolerate them. I believe its more of nature side because you dont choose who you are attracted too and who you fall in love with. its all in the chemicals in your body and the chemistry that you might have with another human being

Jesse 's picture

I think that homosexuality is

I think that homosexuality is a result of both nature and nurture. The two work together; I do not understand why people always think that Nature and Nurture have to achieve two completely different end results. The thing is, both factors can influence the person to be homosexual. The fact that a girl was raised with 5 brothers, and is kind of a tomboy, could be a reason that she is starting to have feelings for girls. It could also be because of the gay gene, which may or may not exist--scientists are not sure yet.

Serendip Visitor's picture

I think homosexuality is a

I think homosexuality is a sickness, and sociall acceptance of it is like standing in a freezer to fight a cold

bob marley's picture



Tony's picture

Categorizing Homosexuality

People shouldn't "think" about homosexuality beyond what research shows. Based on real and viable information, the American Psychological Association removed homosexuality from its list of diseases and disorders in the early 1970's. The decades of research following that removal only compounded data in support that action. Sexual orientation doesn't quality as a disorder and is considered by the vast majority (and ever growing number) of legitimate professionals to be a normal expression of sexuality in nature. If you have a bone to pick with this determination, take it up with the APA, the AMA and AAP and others who fully support this position. I "think" they would know better than most.

Ian.'s picture


Hi I'm straight. My best friend is gay and his mother is a catholic. When he tells his mother that he's gay he will be disowned most likely which is why he's waiting till he's 40.

I believe that people are either born gay or straight so yes I believe in Nature. As for bisexuals I believe they swing towards the sex they were born to naturally be interested in and I believe Nurture causes them to swing the opposite way. I agree with "Tiffany Stroop"; why if someone is straight would they put themselves through so much hate and pretend they are gay? Ok maybe there is a minority that maybe does this for attention or to be 'cool' but those are in the very few. I do not understand the people who 'hate on' homosexual individuals thinking that they had some sort of a choice.

Those are my thoughts, from Ian in the UK.

Amanda's picture

I am a straight female. I am

I am a straight female. I am researching nature verses nuture for a college psychology class. From everything that i have read, including this site. I think it is perfectly ok to like and be with the same sex. To be homosexual these days is everywhere but still frowned upon. I think homosexuality is something that has been around for years and will stay here for many many years to come. I do not understand why people disagree with it, and think it is a sin. To be straight or to be homosexual, in my eyes it is the same. You cannot pick and choose who you love. It is something that just happens. I think people need to just grow up or shut up. If they do not like homosexuals on tv, then turn it off. If they dont like seing them express their love in public because they are jealous tht they cannot find love like that, then look away. Do not judge someone else when you have so many flaws yourself. That is what i think. I have not made up my mind yet if i think homosexuality is nature or nuture, but i do think people need to put on their big people panties now and stop all the childish crap. It's dumb and not called for at all.

Jacinta 's picture


i know that homosexuality is wrong, and it says it right in the bible that thou shalt not lie with another male like one lies with another woman in leviticus 18:22.
so it has to be by nurture. God would not make someone gay if hes agenst it himself.
Also i think that people are grown up about the whole thing it is that they dont agree with it and have every right to look down on it
just think what if you were raised by lezbeins you would be picked on so bad by childern so i think you need to look into it a whole lot more than you are!!!!!!!!!!!!!

Elicia's picture


I was looking for an article for a paper I'm writing when I stumbled upon your comment. The bible was not written by jesus or god. It was written by a bunch of guys who "witnessed god's/jesus's work" so essentially it's no better than a Cosmo or Vogue magazine. So now, in the 21st century you're saying that you're better than a certain group of people and you can look down on them because some homophobic guy wrote it down 2000 years ago in your precious bible. You are among the worst type of people. Good for you for having beliefs honestly but stop kidding yourself before you spread your disgusting comments on the internet. People who are raised by lesbians are picked on by people like you, because people believe what you believe and that's terrible. I'm straight and I was offended by your comment. Sexuality is nature, but how an individual deals with it and lives his/her life is nurture, and because we live in a world where people like you exist it will always be difficult for homosexuals. They are humans just like you, why is it any of your business who they have sex with.

Serendip Visitor's picture

I am so sick an tired of

I am so sick an tired of people using the bible to back up their theory on homosexuality being a choice. Unless you yourself have had a personal conversation with god and he told you out of his mouth that homosexuality is wrong, you need to just stop using the bible for back up. The bible was heavily influenced by man as a way to control society. The bible has been around for centuries and has been re-written and twisted so much that it is so hard to know what to believe. Scientific studies have shown that homosexuality is not a choice that it is a matter or biological reasoning. before people wanna throw the bible into everything. Do you research.

Serendip Visitor 1's picture


i dont get why people say all of these things. homosexuality is real. it cant be changed, and people who are ignorant cant change our minds either.
you guys are referring and freaking out about 2 sentences in the entire bible. thats like... 2000 pages. how does that compare???!!!!

Serendip Visitor's picture

Using the bible as an

Using the bible as an argument is stupid. The bible is only the word of god because the book itself said so.

Tony's picture

Faith versus Fact

Why use an object of faith to deny a natural expression when there is no valid scientific proof in support of the faith itself? Remember that the heart of ANY religion is a matter of faith, not provable fact. No religion could withstand the same level of scientific scrutiny that has been focused on sexual orientation. Keeping that in mind, it would be wise to approach social issues with a tremendous amount of humility when viewing those issues through the lens of religion.

Anonymous's picture

hell yeah im straight i have

hell yeah im straight i have gay friends so what. everyone needs to grow up

Anonymous's picture

I think people are generally

I think people are generally frightened because a species uses procreation to extend itself, evolve and survive. So naturally the idea of something that goes against this grain may be deeply embedded in them as not complying to the survival of the species.
Homosexuality as a minority thing is threatening because it is "different" and humans struggle to accept "different." But then if there is a large majority who practice it, the threat becomes real in the deep sub-conscious of people's minds.This can hardly be surprising. People have very set ways of thinking and usually they cling to what they know because it works for them.
I have no problem with the idea of emotional love between same sex gender, but some of the things we don't talk about is some of the problems caused by same sex activities. Do people really know the problems that can be caused by frequent and/or aggressive anal sex? I have a friend who suffers an ailment due to this and it's really quite horrific. I won't go into details as I don't think anyone would appreciate it. My own personal opinion after much research is that this really isn't how our bodies were designed to function on a regular basis, neither for males or females.
Someone earlier mentioned the fact that we don't condone all behavior just because there are genetic links to it and I thought that was an interesting train of thought. People may then disagree and argue that there is a big difference between a sociopath, and a gay person who doesn't harm anyone, but I think the whole debate stems around the fact that homosexuality as an accepted practice may be harming society as a whole.
People worry about how children for instance, brought up by same sex couples will fare, how young people will understand the world and their own sexuality, the long-standing implications of accepted homosexuality on society as a whole will undoubtedly change it but no-one really knows how. Will the "family" as we know it - the foundation of our societies and therefore our survival, be eroded and irrevocably changed? Homosexuals may be outraged by these notions because they know they don't harm anyone, but even they must admit to having closed doors to other concepts they little tolerate and understand, and so it must be within their reach to grasp why it could be hard for others to change their thinking so dramatically - it's matter of patience. Of course if homosexuality is purely a genetic thing then all these fears are unfounded, but as it has not been proven without a shadow of a doubt, these concerns are still top-most in many people's minds.
It seems that before the word "homosexuality" appeared, most homosexual love in ancient Greece was between a man and a young boy, this also occurred in Crete and New Guinea, so the basis of it was not one of mutual love and respect but of an imbalance of power. As this is our international heritage of homosexuality, it is normal that the fear of it may very well have developed and passed down from generation to generation.
It may be natural, but is it more of a natural anomaly?
I just haven't made up my mind yet. In the meantime I'll be kind and considerate of everyone- irrespective of their gender - as everyone should feel loved and accepted, and will make the effort to understand what I cannot right now. That's as honest as I can get, politically incorrect as it may be.

7anooch's picture


I think that homosexuality is both nature and nurture...nature as in the X chromosome and all..but also nurture (I think peer pressure can play a role) because, this is psychology after all, and whatever a person whats to be they can "think" themselves into being that way, no matter how hard it can be i think you have the power to change who you are..

im not that good in explaining my thoughts I hope you all get it =P

Anonymous's picture

I say who cares if its

I say who cares if its nature or nurture...People shouldn't be judged because of their sexual preference; unless, it hurts someone else(ie children, animals ect.) I have to do a paper on this nature vs nurture..but i just don't care about this subject at is so frustrating what people waste their time trying to figure out. How about we focus more time on the things that really are important..not on why jane likes jane or john likes john...I wonder if people really know the serious environmental things thats gonna take us all out..ooohh its freakin scary...oh well..I love people...I dont even see skin color or sexual orientation..but i do see evil and good souls!

Anonymous straight biracial female.

Marmar's picture

I think all of these people

I think all of these people have good arguments, along with this whole page of works written on it. Im doing a debate tomorrow on nature vs. nurture homosexuality in my psych class. Im for nature just because it seems like the proof is more there than that of nurture. Everyone is raised differently so youll never really know..

Tiffany Stroup's picture

How could someone be so

How could someone be so ignoramt as to say the we, as homosexuals, do not deserve the rights of every other American? How is it just that someone can devote their life to fighting for this country, but be discharged for being with the person that they truly love? We're not pushing to show that homosexuality exists, we're pushing for the rights that we as Americans are entitled to. It isnt't that we care to be accepted more so than we care to be able to have a recognized relationship with our partners.. For the benefits of health insurance, filing taxes, children.. etc. Every right that all heterosexual couples are are entitled to, we should be entited to. It is, in fact, a breach of the constitution not be have those same, equal rights. Our lifestyle does not effect the lifestyles of heterosexuals unless they so choose to allow it to. Those who tell homosexuals that they are wrong and will go to hell for acting upon those impulses would be under just as much religious prosectution for doing so because in their religion, God is the only one who is allowed to judge. Yet are they not judging homosexuals? Is it not for "God" nto decide whats right or wrong? The current Bible that people of the Christian religion base their lives was, in fact, written by man, and has changed very much over the centuries. Many things have been taken out, changed, and added due to the personal opinion and bias or the person writing it. There are some things that were altered because there was no translation. So are Christians, in fact, basing their lives on a book that was written by the every day common man? Maybe you should stop and think before you judge someone on who they truly are. It is your decision whether or not you allow their lifestlye to effect yours in any way. Stop being ignorant.. and take a look at the bigger picture.

Anonymous's picture

hey my children see this at

hey my children see this at the movies and any were they go thats teaching them the wrong way so just do your bussiness secret.

Anonymous's picture

there are so many wrong

there are so many wrong things that your children see everywhere...take drugs, bullying,cheating, stealing....yes YOUR kids see it. Tv, movies, their friends, school, even churches. Its not the society's job to teach your kids its yours. maybe you could...oh...i dont know TALK to your kids about your beliefs. But i dont think you should cuz it seems to me your teaching them hate instead of i guess you should keep letting the tv movies and such teach your kids morals.

Serendip Visitor's picture

amazing the ignorance in this

amazing the ignorance in this world.

Anonymous's picture

i am a homosexual male; i

i am a homosexual male; i can tell you truthfully that true homosexuality is not a choice. granted, there probably are people out there who may 'pretend' to be gay/lesbian/bisexual to go with some sort of trend, but the vast majority of us are not like that. ask yourself: why would so many people subject themselves to torment and abuse, take away their rights to a family?

i wish i wasn't like i am, but i can't change it. i didn't choose to become like this, just like you didn't choose to be straight. nature or nurture is irrelevant - it is definitely not a choice i made. if it was, i wouldn't have made that choice.

z's picture


i'm doing my sociology paper on homosexuality but i am so confused because i don't know what to believe. is homosexuality a gene or a choice? i need facts and i'm just not finding any. i understand that scientists are doing research on the x chromosome and bla bla bla...of which they do have some pretty good arguments to prove that homosexuality is a gene, but then again...what if it really is a choice? i think that has something to do with being a homosexual as well because ive read some article that gave pretty good examples of it....but how in the world would i know...i'm as straight as a line!! i REALLY REALLY would like to find out because a lot of people in my class think it's a choice and i don't know what to think but i want to prove them wrong either way! :)

Random Girl's picture


me too! I'm really struggling to find out what they really think about themselves being homosexual, and I really dont know whether to support them or not.....

CJ's picture

I'm also doing a soc class

I'm also doing a soc class project on this subject "nature or nurture" and I assure you i do not want to be gay, but I am.

Eric's picture


Sociology class! I cant find any arguments on the Nurture side. I have facts from my Brain and Body class but nothing concrete from the web.

allen's picture

thank you!!!!!!!!!!!!

thank you!!!!!!!!!!!!

Diana's picture

Your response was evident of

Your response was evident of the ignorance that still exists in this world today. Unfortunately, there are so many people like you that have been conditioned into this kind of thinking! Unfortunately, it is a small-minded, bigoted and Neanderthal way of thinking, living and believing.