I'm not going to argue that sex is fun, pleasurable, and desired by many people. That's obvious; no-one denies it. Rather, I'm going to argue that sex is morally good, that it is a morally desirable activity, like getting exercise, studying, or helping those in need. Also like them, I will argue that it is not a moral obligation; it is permissible not to have sex, but it is, all else being equal, better if you do than if you don't.
The Need for Argument
Some people might think that the moral goodness of sex is just as obvious as its pleasurable nature. I don't think that most people, even those who think they believe that, really do, and in this section I will show why.
The first, and most obvious, point is that many people hold the contrary view, that sex is a moral evil, and should be restricted as far as possible, particularly if people are enjoying it. This view is, thankfully, becoming less common, but I am fairly sure that it is the majority view world-wide, even if not in the UK or USA. Since there are people who hold this view, there is some obligation to argue against them.
A more important reason is that the culture of the UK and USA is still set up around the assumption that sex is morally dubious at best. Consider a number of example situations.
In the UK recently, a Conservative Party local councillor was forced to resign after someone released a picture of him wearing ladies' stockings, suspenders (garters), and nothing else. He had sent this picture after the person in question said that she was interested, sexually, in older men. The evidence suggests that this was, in fact, a set-up. Now, there is no suggestion that the councillor was harassing the person at the other end of the email. It seems likely that the picture was actually requested, in fact. So, why on earth was he required to publicly apologise and resign? Had he sent a picture of him playing football, there would have been no outcry. The problem is that sex itself is considered morally dubious.
Second, I recently bought a pack of condoms. They were readily available in the shop, and I wasn't made to feel uncomfortable even though it was a woman on the till. But on my receipt they were listed as 'Chemist Goods'. Why? As far as I know, nothing else is so listed -- actual medicines get a named item on the receipt. Thus, the only thing this really seems to hide is the precise brand of contraceptive you purchased. Still, the reluctance to actually put 'Condoms' on the receipt can only stem from a general feeling that there is something a bit wrong with sex.
Third, one of my sisters is currently appearing in a show in California. This is a tradition of several decades standing, where people are posed in the form of great works of art. She is playing the role of a human orchid from the Art Deco period. She's painted gold, and is topless. But she has to wear a small pair of bikini bottoms, because the law in California does not allow her to be completely nude. Again, why? The bikini bottoms are very small, and, as I understand the situation, she will be quite some distance from the stage. What, exactly, is the problem?
Finally, from the ridiculous to the serious. Consider sexual assault. Consider, at its most serious, rape. Rape undoubtedly is more serious than non-sexual assaults causing a similar amount of physical damage, particularly since women can suffer great psychological harm from a date rape that inflicts no physical harm at all. Why is this? Again, it seems that the problem is that there is something bad about sex; the woman has been forced to do something that makes her dirty, makes her less valuable. Consider, by contrast, the psychological effects of being forced, at gunpoint, to save a drowning child. On the one hand, there would be the bad effects of the memories of being compelled to do something against your will. On the other, you would probably be able to draw some comfort from the fact that, even though there was compulsion, you actually saved the child. If people really believed that sex was morally good, on a gut level, the same considerations would apply to rape. The fact that this parallel seems slightly absurd even to me suggests that the cultural feeling that there is something morally degrading about sex is strongly engrained.
So, even people who, at least on the surface, believe that there is nothing wrong with sex may have deep-rooted prejudices against it. Thus, I think it is worth pursuing the argument, and trying to make it more convincing. Apart from anything else, if people really believed that sex was good in itself, rape and sexual assault should become much less psychologically damaging, and that has to be a good thing. Given that rape and sexual assault are, apparently, almost always about power and control rather than sex, convincing people that sex really is a good thing might even greatly reduce the incidence of such crimes. Even if it doesn't, it is better if people have more accurate moral beliefs.
Why Sex is Good
The argument for sex being good is actually very simple; most of the effort is needed to deal with the arguments put forward to show that it is bad.
Sex is good because it is fundamentally an activity concerned with giving and receiving pleasure. Both of these are morally worthy. It is good to enjoy yourself, and it is good to give pleasure to other people.
Sex is good for the same reason it is good to play sports, or good to watch or make movies, or to read or write works of fiction. It is part of the broadly aesthetic component of life, the part that has value because it makes life worth living.
Why Sex isn't Evil
The positive argument is, as I said, extremely simple. More elaborate arguments are required to deal with objections which suggest that it is too simple; that sex is really not morally good after all.
Pleasure is Good
The first, and most fundamental, possible response is to argue that pleasure is not morally good. I am not aware of any way to argue against this response, but equally I know of no way to argue for it. Quite simply, if any moral axiom has the consequence that pleasure is not good, I believe that shows the axiom to be faulty. The moral worth of pleasure simply is a moral axiom, as far as I am concerned, and this essay is not the place to get into the copmlex metaethical issues involved in the selection of moral axioms.
Problems with Gods
Probably the most common argument that sex is wrong is that God has said so.
I have two problems with this argument. First, I don't believe in God.
Second, suppose that there was a God, and that he said this. I believe that this would indicate a moral flaw in God, not a moral problem with sex. This brings us back to the problem of moral axioms, and this essay is still not the place for such a discussion. However, the short version is that I do not think that something can be right or wrong just because God says so, for any concept of God with which I am familiar. Certainly, if God creates the universe, he creates right and wrong, but they flow from the rest of his creation, not simply from his word.
Sex Goes Beyond Reproduction
A very standard argument against sex for pleasure is that sex is intended for reproduction and that any other use of it is therefore wrong. This is the basis of the Roman Catholic Church's morally repugnant opposition to contraception. This argument is flawed in two ways.
First, it is true that the evolutionary purpose of sex is reproduction. However, we use lots of things for purposes that have nothing to do with their evolutionary purpose. For example, I currently have spectacles perched on my nose and ears and, Dr Pangloss notwithstanding, those bits of my head did not evolve to help support aids to vision. There is nothing immoral about using any part of ourselves for a purpose other than the one it evolved to fill.
Second, this argument actually begs the question. It assumes that there is something wrong with sex, so that there needs to be some justification for indulging in it at all. The justification provided is reproduction, so that any sex not involved with reproduction is therefore wrong. But if there is nothing wrong with sex, no justification is needed. You can do it because it is fun, and that is reason enough.
This argument also ties into the animus against manual and oral sex, and against homosexuality. Since these forms of sexual activity cannot lead to conception, they appear unjustified to anyone who has accepted this argument. But if we reject this argument on the grounds that sex needs no justification beyond being pleasurable, manual, oral, and homosexual sex actually have a slightly moral advantage over heterosexual genital intercourse, because they avoid the risk of pregnancy. It is, after all, good to reduce the risks inherent in an activity.
Protecting Children
Another argument that is used fairly often is that children should not be raised in an environment where there is lots of sex going on. Again, this argument is flawed in two ways.
First, just because something is going on does not mean that children have to know all about it. I am sure that most children are more or less completely insulated from the workings of the futures markets, or the details of the United Nations. Even common activities can be kept somewhat out of children's awareness, even if the children are interested. Parents do not always fail completely when they try to throw surprise parties for their children's birthdays, after all.
Second, this argument, once again, begs the question. Children only need to be protected from finding out about sex if there is something wrong with sex. If it is morally good, then there is no problem if children find out about it. As long as they are really children, they aren't interested, and once they are interested it is best to educate them, so that they can minimise the risk. If sex is good, there is no reason to stop teenagers experimenting, only the normal requirement to help them to experiment as safely as possible, and to support them when the experiments go wrong -- just as for any other area of life.
The Moral Relevance of Risk
That raises the issue of the risks involved in sex. Even when all participants trust one another, there is the risk of pregnancy and sexually transmitted diseases. Some people argue that the existence of such risks makes any sexual activity irresponsible, and thus evil.
I disagree. It is possible to take a responsible attitude to risk, and this is what people do in any activity. It is true that having unprotected sex with a different man or woman every night for months is flagrantly, and immorally, irresponsible, since that certainly involves a high risk of spreading sexually transmitted diseases to a large number of people, and, if the active person is male, involves a substantial risk of pregnancy for the women involved. But this is roughly equivalent to taking a group of people mountaineering without safety equipment, or driving without due care and attention. It is possible to take far fewer risks.
In the first place, mutual masturbation, oral sex, and anal sex entail an absolutely minimal risk of pregnancy. Homosexual sex involves no risk of pregnancy at all. Mutual masturbation is also fairly safe as regards sexually transmitted diseases, as it does not bring appropriate environments for the diseases into contact. Within a closed relationship (not necessarily monogamous; it can have a dozen members, as long as it is closed) there is no risk of sexually transmitted disease if no such disease starts within the group. The use of barriers such as condoms also reduces the risk of STD infection to a very low, and morally acceptable, level.
The physical risks involved in sex can be reduced to a minimal level, and then they are far outweighed by the pleasure involved in doing it.
The risks involved with sex are not, of course, entirely physical. There are emotional risks, the risk of the pain of being dumped from a relationship that you wanted. Here, however, the argument is even simpler. These risks only exist because sex is a good thing. People don't worry about being excluded from doing something they hate. The fact that I will never play football for Manchester United completely fails to bother me, because I have absolutely no desire to do so. Similarly, I don't suppose that David Beckham has ever been bothered by his inability to get a lectureship at the University of Cambridge. So, the emotional risks arise because sex is desirable. Given my moral axiom about pleasure, the fact that something is desirable is prima facie evidence that it is good; there may be an argument that it is not, but that argument cannot rely purely on the fact that it is desirable.
Sex Is Not Compulsory
One argument that sometimes gets made against sex being good is that, if it were good, it would be compulsory, and making sex compulsory would be a bad thing.
On one level this is rather reminiscent of the following argument: "I'm glad I don't like broccoli, because if I did I would eat it, and I can't stand the stuff." If sex is good, then the reasons why it would be bad for it to be compulsory become rather fewer.
They do not, however, disappear. Sex is good because it is pleasurable. Compulsory sex would not be pleasurable, at least in the overwhelming majority of cases. Sport is good, but forcing people to play is still wrong. Sex is good, but forcing people to do it is still wrong. If someone really doesn't want to have sex, that's fine.
Roughly speaking, I believe that people have a moral obligation to avoid inflicting harm, and that it is good to provide pleasure. However, there is no obligation to give pleasure. The more you do so, the better you are as a person, but there is nothing morally wrong with simply avoiding harming anyone, and giving pleasure only to people you like. Sex is a good because it gives pleasure, and so while it makes you a better person if you have sex, celibacy does not make you bad. Indeed, if you are celibate to allow you to pursue another good, such as study, or medicine, or even another form of pleasure, more fully, then you might be a better person overall because you don't have sex. Human beings have limited lives, and you might be able to do more good by concentrating all of your energies on medicine than by dividing them between medicine and sex, because your talent for medicine is greater than your talent for sex.
The Problem of Bad Sex
If sex is good because it gives pleasure, what about bad sex, where at least one partner does not enjoy it? Isn't that a bad thing?
Not necessarily. It is, clearly, less good than sex where both partners really enjoy it. But something can be less good while still being good. If one partner enjoys it, then that is good, and the other partner has done something good by providing pleasure. At one extreme, you have the so-called 'sympathy fuck', where one person has sex with another to relieve depression, anxiety, or some similar negative emotion. The sympathetic individual may not enjoy it much, but the desire to give pleasure to someone who needs it is clearly a good thing, and the sexual act in question is therefore good. At the other extreme, you have someone who is simply very bad at sex, but enjoys it, so that his partner lets him do it despite not enjoying it much. Again, this is a good act on her part.
Of course, if neither partner enjoys the sex, then it isn't clear what is good about it. In this case, though, there is little motivation for either partner to continue. If the couple regarded sex as good in itself, and therefore not embarrassing to talk about, they could discuss the issue and find something they actually enjoyed doing to substitute. But in any case, this is not a moral problem; study does not become evil just because some people do not learn very much at school, and sex does not become evil just because sometimes it is no fun.
"Eeuw, icky!" Is Not A Moral Argument
A lot of the purportedly moral arguments against sex, or at least against particular kinds of sex, boil down to the assertion that the person putting forward the argument finds such activities disgusting.
This is not a moral argument. It has no weight at all.
It does tell us that forcing that person to participate in such activities would be wrong, but only because it tells us something useful about that person's preferences. It does not mean that there is anything wrong with people who do not feel that the activities are disgusting engaging in them.
This style of argument is deployed quite frequently against homosexuality, anal sex, oral sex, and fetishes of various kinds. It is, however, quite worthless as a moral argument.
The Unimportance of Ulterior Motives
Finally, people not infrequently suggest that the only reason for making arguments of this kind is a desire to have more sex by convincing people that there is nothing wrong with it.
Even if it is, so what?
If sex is good, then people should be encouraged to have more of it, just as, if learning is good, people should be encouraged to study more. If the basic position is right, then a desire to have more sex is a morally admirable desire, and efforts to persuade people to have more sex are praiseworthy.
This argument is not only ad hominem, it begs the question. It has no weight.
Conclusions
Sex is good because it is fun. None of the counter-arguments I am aware of have much weight with me. The only significant one concerns risk, and that merely requires us to be careful, not to give it up altogether.
Have more sex. It makes you a better person.