How can homosexuality be immoral or contrary to natural ends if there is a genetic/evolutionary/biological reason for it?


This is why the original premise seems so poor to me. Decreased competition? If it exists in both sexes than there isn’t even a decrease in competition. Plus there are so many easier examples. What about people that identify with asexuality? i.e. People that have little to no sexual desire.

Plus, infant and child mortality used to be sky high. People often needed to have multiple sons and multiple daughters.

Humans have been around for hundreds of thousands of years and the entire “sexual orientation” fad began within the past 100 years. Before that, it was commonplace for homosexuals to still be in heterosexual relationships. Heck, even pagan cultures that were permissive to homosexual acts still viewed heterosexual relationships as the ones that were fundamental to society. Homosexual relationships with another man or with an adolescent boy were for companionship and pleasure, but they weren’t the building block of the society and people recognized that.


There’s no reason to think that evolution makes things moral.


Perhaps mans capacity for “self control” has evolved as an evolutionary means of birth control. Perhaps giving free rein to our every sexual impulse is actually bad for us as individuals and as a species. Perhaps it is our capacity to restrain impulses with reason that has elevated us above other species.

It never ceases to amaze me that our embrace of our own helplessness In the face of our own sexual urges is called progress.


It is a faulty assumption that everything that has an evolutionary explanation is necessarily moral. There are many behaviors that have evolutionary explanations that no reasonable person would call moral. For example, when a male lion takes over a pride, he kills the cubs of the previous male before fathering cubs of his own. This behavior has an obvious evolutionary explanation. Individuals who favor their own offspring over others will have more descendants in the next generation than individuals who treat all members of their species equally. Lions have taken this to the extreme. The male does not want to waste any of his resources on someone else’s cub when he could be devoting himself entirely to his own cubs. But no reasonable person would claim that this justifies infanticide by a step-father among humans.

So just because homosexuality can be seen to serve some practical purpose, that does not mean it is moral. To the extent that it serves some “natural end”, it is an end that is a feature of fallen nature. Not every feature of fallen nature is to be acclaimed as good.


Forgot the TED talk. The premise is not even close to having any proof for it.

Next, replace the word “homosexuality” in your question with the word “vice”, and remove the phrase “contrary to the procreative faculties”. After all, there are several kinds of sexual desires, and they may even exist on a spectrum, so there’s no point in singling out homosexuality.

I believe that the same conclusion could be arrived at by inserting any “vice” into the question. (Homosexual acts being the vice. SSA is not considered a vice.)

The answer, I believe, relates to our being made in the image and likeness of God, but lacking the perfection that God has.

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I don’t know about non-religious reasons for classifying it as immoral, but there are certainly non-religious reasons for classifying it as non-procreative.

You seem to think that the genes for homosexuality are in the human being rather than in some other organism: Pathogenic theory of homosexuality

There is an evolutionary reason for homosexuality, it benefits some as yet unknown disease organism.

Is there then a reason for rejecting this behavior? Yes, because it spreads disease, both opportunistic infections and the infection that originally generated it.

Based upon that theory, I would say that voting an illness to be normal only serves to spread the disease.

Note: I’m not clinging hard and fast to this explanation, but you asked for a reason from a source that was non-religious and contrary to the procreative faculties (i.e. sick or diseased), so I gave you one.

So if any given sex act did not ‘spread disease, both opportunistic infections and the infection that originally generated it’ then we could omit this reason for rejecting it.

Is your question a religious one or a non-religious one? The OP was asking for something non-religious, so in that case not every act counts, only the general presence of acts spreading a disease.

If I was speaking solely in religious terms, then I would have simply said God doesn’t want these things to be done, but the OP explicitly said he doesn’t want that as a reason.

In more general terms, we are (or perhaps I should say I am rather than we are) speaking of epidemiology, not morality.

Seriously, I trust we don’t have to become so pedantic as to have to argue about why it’s wrong to spread diseases. Even though that is moralistic, it’s also just too trivial.

Yeah, right.

Made-up hypotheses about Darwinian fitness aren’t sound premises, though. Neither is the implication that St. Thomas would have agreed that it is inherently moral to act on any impulse prompted by an identifiable deep-seated natural cause.

That premise is absurd on its face. Whatever people are prone to do would be something a Darwinian would say must have some kind of evolutionary advantage. If not, after all, the behavior wouldn’t be preserved. Logically, then, morality would be in just doing our best to follow our instincts or natural impulses. Gossip? It must be ethical, because we’re so obviously prone to do it that it must have a natural cause! Lying to evade punishment? Also deep-seated…must be natural and therefore, it must be ethical.

Well, what about the natural advantage of being able to understand and master our impulses?

More to the point: Are you really arguing that the human race should not attempt to develop any virtue or even to consider something a virtue if some impulse towards the corresponding vice could be shown to have a genetic basis?


No. It is a distorted image, like a funhouse mirror image. Sad for those afflicted with the inclination, however, they have free will to act on the inclination or not.

Homosexual acts in the wild are opportunistic and instinctual.

Is it the claim man cannot overcome these and is simply an opportunistic and instinctual animal without the rational ability to make a cholce?

Things that check overpopulation:

  1. Genetic mutilation
  2. War
  3. Bestiality
  4. Murder
  5. Suicide

The same argument could be used to say that any medical condition that has a genetic vector is not to be seen as a disorder that requires treatment. Sickle cell anemia, asthma,… it’s a very long list.

IS there an explicit genetic/evolutionary/biological reason for it? You have a TED Talk which claims there is. I don’t see any scientific source backing the claim.
Even if there was an evolutionary need for birth control why homosexuality? Why not just fertility reductions or lack of sexual urges?
And how many times in human history has reduction in birth rates been evolutionarily desirable?


Sickle cell is an interesting example. It is caused by a gene that is disadvantageous in duplicate but advantageous when the organism only inherits one copy. If you have just one of the sickle cell gene, for instance, you are resistant to getting malaria.

So–if there is a mechanism by which women develop an immune response to proteins that affect the development of the brains of male babies, it does not follow that the result of the highest response is the reason the response is advantageous. In the case of sickle cell, the great advantage of the partial response is what makes the disadvantage of the full response “worth it” in a Darwinian sense.

In other words, establishing a natural cause for something does not establish that the thing is what is advantageous. It only suggests that the natural cause OVERALL has an advantage or is associated in some way with an advantage.

So sure, it could be that in a family with all male children there is an advantage for the family if the later siblings to be less aggressive or less dominant or more…whatever. We know so little which of the differences in our brains are based on genetics, let alone what is based on sex or sex hormones. We really don’t even know what is learned and what is intrinsic or how the factors combine. It is hard to do anything but speculate.

It is certainly jumping the gun to say that homosexual behaviors are advantageous to the species, even from a purely secular or naturalistic view.

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There are studies indicating that homosexual orientation is more prevalent in men who have older brothers and that there is an immune response in mothers that can be tied to this observation.

It’s a line of study currently…

There weren’t many people practicing homosexuality until the government started mandating that everybody tolerate it. Whats worse is it is not only taught in school that is it acceptable but it is also proliferate to the youth.

If beastiality was tolerated and proliferated like homosexuality, there would be scientists trying to rationalize that choice with a genetic/biological side to it as to make it more acceptable to the public.

The fact of the matter is God does not etch the “big gay” into people’s genes. The implications would be ridiculous and would make God a maniac.

Homosexuality, like pedophilia, beastiality and other sexual perversions are a choice, not a biological constant. Homosexuality cannot make life. It is literally impossible.

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There isn’t, albeit gay people will claim they are born gay. Nobody is born gay.
People become gay as a product of upbringing and/or environment and/or choice!


Which has nothing to do with what I said.

So just to be clear here, I’m sure that everyone who has a work colleague or a friend or a daughter or a father who is gay wants to know if you’re comparing the person they know and love to someone who rapes children or has sex with animals.

Have I got that right?

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