Sex is an important part of life. For many men, thinking about sex starts early, often before puberty, and lasts until their final days on earth.On one level, sex is just another hormone-driven bodily function designed to perpetuate the species. On another, it's a pleasurable activity. It's also an activity that can help cement the bonds between two people.Premature ejaculation occurs when a man reaches orgasm and ejaculates too quickly and without control. In other words, ejaculation occurs before a man wants it to happen. It may occur before or after beginning foreplay or intercourse. Some men experience a lot of personal distress because of this condition. As many as one in five men experience difficulty with uncontrolled or early ejaculation at some point in life. When premature ejaculation happens so frequently that it interferes with the sexual pleasure of a man or his partner, it becomes a medical problem. Several factors may contribute to premature ejaculation. Psychological problems such as stress, depression and other factors that affect mental and emotional health can aggravate this condition. However, there is growing evidence that biological factors can make some men more prone to experience premature ejaculation