Masturbation, or onanism, is stimulation, often manual, of the genitals for sexual gratification. Masturbation is depicted in prehistoric cave paintings and has been observed in many species of animal. In Egyptian myth, the god Atum created the universe by masturbating, and pharaohs ritually masturbated into the Nile. In some traditional cultures, masturbation is a right of passage into manhood, although there are some groups, notably in the Congo Basin, that lack a word for masturbation and are confused by the concept. Alternative and divergent sexual practices such as masturbation and homosexuality are associated with peace and abundance: In unstable traditional societies with high infant mortality, the spilling of semen may be perceived as unnecessary, extravagant, or wasteful. Although ejaculation is a rite of passage for young men of the Sambia tribe in New Guinea, it is brought about by fellatio so that the semen can be ingested rather than spilt. The Ancient Greeks regarded masturbation as entirely normal, if more the province of the common man, since the elites had a duty to further the family line, and also had slaves for their relief.


Christianity, of course, adopted an altogether different view of masturbation, rooted in an obscure passage of the Book of Genesis. When God killed his eldest son Er, Judah told his second son Onan to marry Er’s widow Tamar and ‘raise up seed’ to his brother. But when he lied with Tamar, Onan spilt his semen on the ground—presumably because he knew that fathering a son in the name of his brother in a levirate marriage would have cost him the larger part of his inheritance. This displeased God, ‘wherefore he slew him also’ (Genesis 38:10 KJV). In the 18th century, the physician Robert James, a friend of Samuel Johnson, professed of masturbation that ‘there is perhaps no sin productive of so many hideous consequences’. More subtly, if still unconvincingly, the philosopher Immanuel Kant argued that ‘a man gives up his personality … when he uses himself merely as a means for the gratification of an animal drive.’


In the 19th century, Jean-Étienne Esquirol, an eminent psychiatrist and physician-in-chief at the Salpêtrière Hospital in Paris, declared in his classification of mental disorders that masturbation is ‘recognized in all countries as a cause of insanity’, and it is not until as late as 1968 that masturbation finally fell out of the American classification of mental disorders, then the DSM-II. In 1972, the American Medical Association pronounced masturbation to be normal, but the guilt, shame, and stigma still live on to blight people's lives. In 1994, the Surgeon General of the United States Joycelyn Elders had to resign after opining, in the context of preventing young people from engaging in riskier forms of sexual activity, that masturbation 'is part of human sexuality, and perhaps it should be taught'. Even more tragically, in 2013, a 14-year-old American boy took his life after a classmate filmed him touching himself in the changing rooms.
There is no doubt that masturbation can present a problem if it becomes distracting or distressing, undermines relationships, or is carried out in public, but it does not make people go mad, blind, impotent, gay, or anything of the sort.
To the contrary, masturbation has a number of important benefits:


1. Pleasure and convenience. 
 Upon being challenged for masturbating in the marketplace, the ancient philosopher Diogenes the Cynic replied, 'If only it were so easy to soothe hunger by rubbing an empty belly.' He claimed that taking pity on his son Pan, the god Hermes gave him the gift of masturbation, which Pan then taught to the shepherds. Masturbation has no need of special equipment, sexual intercourse, or even a partner. Although masturbation is often regarded as the poor relative of sexual intercourse, many couples engage in mutual masturbation, either alongside or instead of intercourse, to simplify, improve, or enrich their sexual lives and arrive at orgasm.

2. Fewer complications. Masturbation is safe as well as convenient. Unlike sexual intercourse, it is very unlikely to lead to pregnancy or sexually transmitted diseases such as human papilloma virus, chlamydia, gonorrhea, syphilis, herpes, and HIV/AIDS.

3. Stronger, more intimate relationships. Contrary to popular perception, there is, at least in females, a positive correlation between frequency of masturbation and frequency of intercourse. People who masturbate more are more sexually driven, and mutual masturbation is likely to increase the frequency and variety of sexual contact. Both in the performance and the observation, masturbation can teach partners about each other's pleasure centers, preferences, and particularities. If one partner is more sexually driven than the other, masturbation can provide him or her with a balancing outlet.

4. Better reproductive health. In males, masturbation flushes out old sperm with low motility and reduces the risk of prostate cancer. If practiced before sexual intercourse, it can delay orgasm in males suffering from premature ejaculation. In females, it increases the chances of conception by altering the conditions in the vagina, cervix, and uterus. It also protects against cervical infections by increasing the acidity of the cervical mucus and flushing out pathogens. In both females and males, it strengthens muscles in the pelvic floor and genital area, and contributes to extending the years of sexual activity.

5. Faster sleep. Masturbation promotes sleep by reducing stress and releasing feel-good hormones such as dopamine, endorphins, oxytocin, and prolactin. Orgasm, in particular, brings on a state of stillness, serenity, and sleepiness, sometimes called 'the little death' (la petite mort), which can usher in a deeper sleep.

6. Improved cardiovascular fitness. Masturbation is, in effect, a form of light exercise. Compared to regular exercise, it is more effective or efficient at reducing tension and releasing feel-good hormones. The muscles and blood vessels relax, improving blood flow and lowering heart rate and blood pressure. No surprise, then, that there is an inverse correlation between frequency of orgasm and death from coronary heart disease.

7. Brighter mood and other psychological benefits. Masturbation reduces stress and releases fell-good hormones, which lift mood and reduce the perception of pain. It promotes better, more restorative sleep, locking in sleep's myriad benefits. It enables younger people in particular to explore their sexual identity and master their sexual impulses, which can lead to a happier and healthier sexuality, as well as greater self-awareness, self-control, and self-esteem. It provides an escape from the demands and limitations of reality, an outlet for the imagination in fantasy, and a medium for the memory in nostalgia. And it culminates in a transcending experience that unites mind with body and life in death.