Does everyone do it? Or has everyone done it? The answer is yes!

For some people, masturbation is actually the high point of their day. The celebrated gynecologist Hector Treub put it succinctly: 'We've all masturbated and those who say they've never done it are still doing it!'

Of all sexual actions, masturbation remains the most difficult one to discuss openly. When it is good it is a strictly personal experience, which many people have learned quite wrongly is dirty, sinful, shameful or even unhealthy. It is, however, the most common human sexual expression and is perfectly normal.

Why do we do it? Is it because sex with our partner does not satisfy us? Because there is no partner? Because men watch porn and can't contain themselves? Because women read exciting, erotic books? Is it a universal physical need? In my view, none of those questions are very relevant. Masturbation is not a hobby of profligate, hedonistic individualists. The cranking up of the machine is a thing in itself, without a moral component. Nothing to worry your head about. Masturbation is relaxing for both men and women and acts as an excellent soporific, without side effects. Apart from that, it is free.

Many modern sex education books suggest that masturbation is a good way of discovering one's own body. In that way, they argue, the adolescent is better prepared when he or she starts having sex with a partner. That seems to imply that masturbation is fine, but is unnecessary once one is in a relationship. However, recent surveys indicate that almost all men masturbate, at all ages, even when they are in a relationship. The percentage of women who masturbate is lower than that of men. Many women still feel embarrassed when asked about masturbation and the suspicion is consequently that a considerable proportion still answers incorrectly in the negative. In fact, for many women it is their only means of achieving orgasm. And then there is the fact that, in comparison with men, women have the great advantage that for them masturbation causes no mess and usually leaves no visible trace.

For several centuries masturbation was considered as a "sinful affliction." In around 1712 the British surgeon John Marten, in a treatise entitled Onania, or the Heinous Sin of Self Pollution (inspired by the Old Testament figure of Onan, punished for choosing to pour his seed on the ground rather than father a child on his late brother's wife), describes 'onanism' as a new disease. Marten explains that masturbation is widespread and frequently practiced out of sheer ignorance: 'Through solitude or vanity boys learn self-abuse and self-pollution, without knowing how wrong and dangerous it really is.' His treatise became a veritable sensation, and sold widely. Published in medical journals and ordinary newspapers it found its way all round Europe.

Like many of his colleagues Marten, did not act completely without self-interest, and in fact placed advertisements for all kinds of medicines, such as vaginal drops, penis ointments and powders, all designed to curb solitary sexual gratification, in the same papers in which his article on the "new" disease appeared. In view of historians, the great success of both his moral condemnation and the sales of his cures - he created his own pharmaceutical industry - made Marten the originator of the taboo. In his wake, progressive philosophers like Kant and Rousseau adopted the same vision: masturbation did not fit into the new image of man as a rational, social being who had to keep his own desires and urges completely under control. Masturbation sprang from the imagination and bore no relation to reality, and made people susceptible to addiction.

Much more misunderstanding about masturbation can be traced back to the 18th-century physician Samuel-Auguste Tissot (1728-1797). A world-renowned doctor, he produced one of few texts of the time about masturbation, despite knowing little about the topic. Sadly, it was his fame, and not the document's content, that made it an influential work. Tissot assumed that sperm was a form of concentrated blood, so release without the prospect of impregnation was not just wasteful but dangerous. His list of ailments afflicting those who masturbate - including, as you may expect, eye disease and blindness - fills pages. He also described how the masturbator's brain could dry out to such an incredible extent that it could be heard rattling in the skull! His theory was as follows: orgasms achieved through masturbation were produced via the imagination. In other words, the brain overheated.

At any rate, Tissot's ostensibly scientific approach did have a considerable influence on the development of the anti-masturbation movement. Not only doctors, but many clergy and pedagogues accepted his ideas. The masturbation fallacy was certainly grist to the mill of the Christian churches - the moral theologians could not believe their luck! "Go forth and multiply," as it says in Genesis. Down the ages, generally speaking, spilling one's seed has been regarded as sinful or as a necessary evil in most cultures and religions. The history of the safeguarding of the position of sexual intercourse for the purpose of reproduction is an immensely long one.

For centuries, the commandment "thou shalt not masturbate" which became a paradoxical fusion between the progressive spirit of the Enlightenment and conservative ecclesiastical views, held the community morally in its thrall. Far into the twentieth century, masturbating patients were informed of the gruesome consequences of their behavior: mutilation, blindness, hysteria, aggression and madness (particularly in women), kidney disorders or a deformed spine, the familiar endless litany. This pathology sparked a new industry, supplying products like erection alarm apparatuses, penis sheaths and, for girls, special gloves and bandages to prevent them from opening their legs.

The fact that knowledge did not prevent people from continuing to masturbate indicates that moral crusaders have little or no influence over human actions. Possibly prohibition actually gave a stimulus to the precursors of today's porn industry, since the denunciation of the sin on an ever-wider scale was paralleled by a lively trade in prints showing men and women in states of solitary, blissful sensual abandon.

Are there steps that can be taken to prevent people agonizing about masturbation? Yes, simple sex education from parents, whether or not with the support of a booklet or a good internet site, a few lessons at secondary school, and perhaps it would make good sense also in the education of social workers, nurses, doctors and psychologists to have a few lectures on evolutionary biology, since it is clear from that science that masturbation is not only a pleasurable but also a very meaningful activity. Evolutionary biologists see masturbation as an important aid in what is called the "sperm competition." Sperm cells that have been stored for too long start to show abnormalities, such as abnormal heads, or no heads at all. For that reason a regular turnover - of between three and five days, it is estimated - is important in the context of reproduction. If that, for whatever reason, is not possible through sexual intercourse, masturbation offers a way out. However, daily masturbation is not sensible, because in that case the number of sperm cell per milliliter falls too sharply.

Perhaps masturbation in a sociological sense is comparable with the ambivalent stigmatization of the single individual as opposed to the individual in a permanent relationship. The former is not only pathetic because he or she lacks love and care, but is also selfish. The same thing may apply to the adult masturbator: they are alone, pathetic and selfish. That applies of course to both men and women. I fear that for many people it will be a long time before they achieve non-compulsive, fantasy-filled masturbation. The same applies to adequate sex education for our children. It will definitely never reach the point where masturbation lessons take their place alongside swimming and traffic-awareness lessons. That can only happen when we have left behind the eternal glorification of sex issuing in sexual intercourse behind us. That attempt is no doubt doomed to failure. The reality is that the number of singles is rising. Masturbation has a deeply murky past, but solitary sex has a "golden future" ahead of it.

Mels van Driel is the author of With the Hand: A History of Masturbation.