Even if it’s ‘technically true’, is it useful?
I mean, it might be ‘technically true’ that people with red hair have some sort of ‘melanin disorder’, but even if that’s true, is it useful to call it that?
I don’t think it’s useful as ignorant people will definitely use this disorder thing for stigmatization. But we’re talking about how true this statement is, not about how useful it is.
There are different sorts of “truth” involved. “Technically” suggests a factual analysis, “fair” is an a priori value judgement.
Likewise, the argument that physical homosexual intercourse (as distinct from same-sex relationships in a broader sense) cannot of itself lead to procreation, therefore it must be a “disorder”. The first is factually true, the second is an a priori value judgement, and only true to the extent that you accept the underlying assumption that there is an “order” from which this is a “disorder”.
Woah, woah, woah. As they say, “cite?”
Rape may not be ideal, or what we want to encourage, but it is undeniably “natural.” It’s probably responsible for you and I both being here to have this conversation. Despite inspirational memes about being the result of the love of thousands, the sad fact is that you are more likely the result of the love of hundreds, the rape of hundreds, at least a few drunken accidents and a failed contraceptive device.
Dolphins rape. Ducks rape. Chimpanzees rape. Humans rape. I’m sure even more animals than that rape. Rape is not only natural, it’s quite possibly evolutionarily adaptive. It’s a great way to spread your DNA widely and then not invest your time and energy raising your offspring.
“Natural” =/= Good
But if he’s arguing from an evolutionary theory perspective, then your best bet is to point out that it appears that humans, “naturally”, are a little more like wolves than robins. We don’t “naturally” have offspring for every mated couple, nor does every individual form a mated bond with another. Rather, we, as a family, are invested in the offspring of our siblings. We support the spread of our DNA indirectly by NOT all breeding, but concentrating our resources on our nieces and nephews if we ourselves don’t mate. And no one is better at spoiling kids rotten than a gay uncle.
“Aberrant” does not equal “disorder.”
Gay people have an aberrant sexuality. They often have to go through socially aberrant means to procreate.
But people are only considered “disordered” when they are disabled in some significant way. A person who hears voices but is able to live a functional, happy life is not disordered. A person who hears voices and can’t function well enough to have a happy life has a disorder.
Eh. That’s a bit like asking how to boil babies separately from asking “Why the hell would anyone ever want to?”
Do you really think this board couldn’t have a rousing debate on the optimal method for boiling babies? I assure you, we could. And probably have. 
It would probably have to split into several threads after hijacks on steaming and grilling - and debate on whether poaching is the same as boiling.
I don’t think it’s wrong to discuss whether condition X is technically a ‘disorder’, but when the topic is as divisive and emotive as this one, I think it’s perfectly fine to question people’s motives for wanting to classify it as such.
It’s not any more fair than treating “Don’t want to have babies” or “don’t want to marry any of the women I’ve met so far” as personality disorders. They are quite normal and frequent variations on the human condition and treating them as disorders because they lead to a good chance of being an evolutionary dead end as an individual is silly.
In an attempt to get a sterile baby, some folks would balk at the “dangers” of irradiating the infant. We see this already with the irradiation of foodstuff. Boiling babies seems inevitable.
While I agree with your sentiment, I still think there’s a subtle difference between homosexuals and child-free people. For child-free “don’t want to have babies” can change tomorrow to “okay, I’ve met a right person, I want to have babies” and after that they can naturally procreate.
And so can homosexuals.
Are people actually under the impression that homosexuals cannot have sex with an opposite gender partner? Most of them can, with perhaps the exception of some men who cannot maintain an erection with a woman, but most can. They just prefer not to.
The same is true for gay folks, and has happened many times. If the heterosexual couple needs IVF to have a kid it doesn’t raise any eyebrows, why would the same hold true for a same sex couple? There are differences, but in this case they aren’t meaningful differences.
Perhaps they can. What if there are fertility problems? There’s a thriving medical specialty devoted to helping couples unable to procreate.
What if the woman meets “her” guy after menopause? What about wives & mothers who’ve passed menopause? Do husbands have the right to discard them for young nubiles? (Viagra can work wonders!)
Even people who want kids often have sex without wishing to conceive* that very moment*. Ever hear of contraception? Some people regard that as unnatural, too…
The guy mentioned in the OP is, in fact, homophobic.
Do left handed people have a “disorder”?
But infertile heterosexuals do have a disorder, right?
In what way are left-handed people biologically limited?
In no way; neither are gay people. If gay people want to reproduce they have many options, including the “conventional” route, unless they are not fertile.
My argument would be that calling homosexuality a sexual disorder is a distinction without a purpose. As others pointed out, homosexuals can and do often have children, even without resulting to modern science. Certainly in the past, there were plenty of gay men and women who had been socially pressured into getting married and having children. Even today, they can still find someone who is willing and able to have children with them and handle it the old fashioned way.
There’s nothing physiologically or biologically wrong with them in the way that, as the OP’s example compares, there is with color-blindness. Not seeing color is something clearly deficient. It’s not socially wrong and it’s not debilitating like actual blindness, but it’s still something clearly not working the way it does for most people. I don’t think it’s a fair analogy to compare homosexuality to some sort of physiological disfunction because it’s not.
Further, just because typical homosexual sexual acts don’t result in the possibility of procreation, does that mean that any sexual act that doesn’t or isn’t intended to is some sort of disorder? Again, as mentioned by the OP’s example, if someone is bisexual it somehow isn’t a disorder, but what if they only ever pursue relationships with the same sex? What if a straight couple is into oral or anal or never intends to have children so they get snipped or tied or use contraceptives? What if a straight person just can’t get someone willing to sleep with them or is content enough just masturbating? What if someone is asexual? What if someone chooses to forgo sex for some reason, like becoming a monk or a nun or a priest?
And what if the opposite is true? What if someone is full on heterosexual, is primarily interested in normal sex that could result in procreation, and maybe they even want children, but they’re infertile or just have difficulty conceiving for some reason or another? There’s clearly some sort of problem there, but that they can never procreate doesn’t make it a sexual disorder, it’s probably a disorder of some sort, but sexual doesn’t make sense.
And even if we do call it a disorder, so what? Disorders are treated it some way. If there’s nothing wrong with it socially or biologically and there’s no treatment to be done, what does calling it a disorder accomplish?
In no way.
Your friend’s logic boils down to this in it’s barest form:
90% of brains work like A.
10% of brains work like B.
Therefore, B brains are abnormal by mere virtue of being in the small minority.
Only except, you have to question one’s motivations as to why they want to debate this topic when it has to do with sexual orientation. Why aren’t they making the same argument for left handed people?
One has to wonder given the history gay folks have had to endure.