Against nature? Is that even possible? Doesn't the fact that we're capable of feeling a particular attraction automatically mean that it's within the range of natural possibilities?
Most of us certainly don't feel that we're choosing to go against nature. Against puritanical cultural dictates, certainly—but not against nature. In fact, some of us might even argue that it's those who practice exclusive hetero- or homosexuality who are choosing to go against nature. There's very little evidence to indicate that there are many complex species at all, and especially not mammals, in which it is at all common for animals to limit their sexual activities solely to partners of the opposite sex. For insects, yes, it can be argued that exclusive heterosexuality is normal—but the more complex the animal species you name, the less evidence there is to indicate that members of that species are normally exclusively heterosexual. For primates especially, as the "Beastly Bisexuals" article listed on our Other Related Links page discusses, current research indicates that all members of all primate species except humans regularly indulge in sex with partners of all genders. And there's even more extensive research showing that humans themselves in many cultures and historical eras have not been divided into any categories remotely resembling the typical modern "90% heterosexual" statistics. For more information on human cultures which lacked the concept of exclusive heterosexuality, try our Social Constructionist History Links page or, better yet, read a few of the books listed in the Social Constructionist Books section of our Queer by Choice Books page.
Furthermore, if people's sexual preferences were allowed to develop naturally and without social pressure, like the preferences of our primate relatives, one would expect that in a society with strict gender roles there would be far more people who'd prefer their own sex than who would prefer the opposite sex. Most people typically form their most intimate relationships with others of their own race, class, and religion, and having had a similar cultural upbringing to one's partner often makes it easier for the two of you to relate to each other. Heterosexuals know very well how difficult their gender differences can make it for them to relate to their partners—witness the proliferation of bestselling books like Men Are from Mars, Women Are from Venus, which purport to help hetero partners "translate" their words into each other's different "languages." Trying to bridge cultural gaps is all very well, but if people were choosing their partners for healthy reasons instead of from sheer terror of being called "queer," one would expect that it would be more common to form intimate relationships with people who do speak the same language than with those who don't.
Our bodies were not designed with exclusive heterosexuality in mind. Bodies do not even come in two genders in the first place—they come with a range of sexual organ configurations which can include at least ten different possible chromosomal patterns from XXX to XXY to XO, as well as one or more ovaries and/or testicles, an orifice which may or may not lead to a womb, and a protuberance which may or may not include ejaculatory or urinary functions at its tip, and which, regardless of what functions it performs, doctors label as a "penis" or "clitoris" primarily based on its size: if a baby's sexual organ protuberance is under about half an inch wide and half an inch long then they label it a "clitoris" and suggest surgery if "needed" to make it more closely resemble the doctors' ideas about what a "clitoris" should look like; and if it's about half an inch or more wide and long then they label it a "penis" and again suggest surgery if "needed." But the surgery is in fact rarely really needed—most babies' nontraditional sexual organs are quite functional, often fully capable of reproduction (occasionally even in more ways than one), and always quite capable of being made love to by people of all possible sexual organ configurations. And as for people with different chromosomal patterns—most people who have them never even find out about it. At one point the Olympics Committee made chromosomal karyotyping a requirement for all female athletes to "prove" they were "real" women. Guess what happened? They disqualified such a huge percentage of athletes and upset so many women who would never otherwise have suspected themselves of being anything other than female, and who in some cases had even given birth to children and considered that quite sufficient proof that they were "real women," that the Olympics Committee was forced to remove the karyotyping requirement. Now then: what does the concept of "heterosexuality" mean for these people? Did Nature, God,or whatever Creator you believe in create these people this way just to forbid them to ever have sex with anyone? Be serious. What kind of a Creator would that be?
Exclusive heterosexuality is not ordained by any higher force than human culture itself—it is a human byproduct of the terror and cowardice promoted by a twisted religious belief which pretends that sex exists only for reproductive purposes and condemns every form of nonreproductive pleasure, from masturbation to queer sex to all forms of birth control. Sex has never existed only for reproductive purposes, and it never will exist only for reproductive purposes. It exists for social purposes, as an expression of love and an important part of emotional bonding. Animals use it to demonstrate trust, welcome a newcomer into a social group, or facilitate cooperation in any task. This is why both human and animal bodies are designed in ways that encourage us to take pleasure in the bodies of all those around us. Evolution selects for it because it is an advantage. The ability to enjoy sex with both genders encourages cooperation with both genders and this makes it easier for the whole species to survive.
There are so many ways in which Nature, God, or whatever Creator you believe in seems to have gone out of Her/His/Its way to make it easier for people of the same sex to make love to each other. Men have special pleasure receptors in their prostate glands which intensify orgasm, and which can only be stimulated if they are anally penetrated. Why do you think those are there? And what about the structure of women's sexual organs—why is the clitoris located outside of the vagina, making it necessary for a man to rub a woman's clitoris with his hand or tongue to bring her to orgasm because plain vaginal penetration just doesn't do it for most women? If women's bodies were designed solely for reproductive heterosex, it would be ridiculously stupid to put the clitoris anywhere but inside the vagina. But for lesbian sex it is convenient to put the clitoris where it is, so that it is easily reached in a wider variety of ways. Isn't it fascinating that the clitoris is located here, where it is most convenient to lesbian sex, and not in the vagina, where it would have been far more convenient for reproductive heterosex?
As Alfred Kinsey once said, "The only unnatural sex act is one which you cannot perform." In other words, if Nature, God, or whatever Creator you believe in had not intended for a man to be with a man and for a woman to be with a woman, why would She/He/It have provided all of us with a wide variety of orifices and sexual organs that all rub up so pleasurably against each other? If the Creator had wanted to make us all hetero, all the Creator needed to do was stick our glans sexual organs way at the back of deep tunnels and then provide only the opposite sex with tentacles of the proper shape to fit into each other's holes. Instead of doing that, She/He/It put both the penis and the clitoris out in easy reach to be made love to by anyone at all. Hmmm . . . maybe there's a reason for that!