Normal person's sexual attraction to another, the passion and love that follows are deeply associated with the intimate happiness which is determined by anatomy, physiology, living style, relationship with the other person and developmental experience throughout the life Normal sexual behaviour brings pleasure to oneself and one's partner, involves stimulation of the primary sex organs including coitus; it is devoid of inappropriate feelings of guilt or anxiety and is not compulsive.
The surface of the brain is involved in controlling both sexual impulses and processing of sexual stimuli that may lead to sexual activity. In studies of young men, some areas of the brain have been found to be more active during sexual stimulation than others. Many neurotransmitters (chemicals in the brain: dopamine, epinephrine, norepinephrine, and serotonin) are produced in the brain and affect sexual function. For example, an increase in dopamine is presumed to increase libido. Serotonin, produced in the upper pons and midbrain, exerts an inhibitory effect on sexual function. Oxytocin is released with orgasm and is believed to reinforce pleasurable activities. Sexual arousal and climax are ultimately organized at the spinal level. Sensory stimuli related to sexual function are conveyed via various nerves like the pudendal, pelvic, and hypogastric nerves.
Testosterone increases libido in both men and women, although estrogen is a key factor in the lubrication involved in female arousal and may increase sensitivity in the woman to stimulation. Progesterone mildly depresses desire in men and women as do excessive prolactin and cortisol. Oxytocin is involved in pleasurable sensations during sex and is found in higher levels in men and women following orgasm.
Arousal is triggered by both psychological and physical stimuli; levels of tension are experienced both physiologically and emotionally; and, with orgasm, normally a subjective perception of a peak of physical reaction and release occurs. Psychosexual development, psychological attitudes toward sexuality, and attitudes toward one's sexual partner are directly involved with, and affect, the physiology of human sexual response. Every normal human being has four-phase sexual response cycle.
Masturbation is usually a normal precursor of object-related sexual behaviour. No other form of sexual activity has been more frequently discussed, more roundly condemned, and more universally practiced than masturbation. With the approach of puberty, the upsurge of sex hormones, and the development of secondary sex characteristics, sexual curiosity intensifies, and masturbation increases. Adolescents are physically capable of coitus and orgasm, but are usually inhibited by social restraints. The dual and often conflicting pressures of establishing their sexual identities and controlling their sexual impulses produce a strong physiological sexual tension in teenagers that demands release, and masturbation is a normal way to reduce sexual tensions. Moral taboos against masturbation have generated myths that masturbation causes mental illness or decreased sexual potency. No scientific evidence supports such claims. Masturbation is a psychopathological symptom only when it becomes a compulsion beyond a person's willful control.Then, it is a symptom of emotional disturbance, not because it is sexual but because it is compulsive. Masturbation is probably a universal aspect of psychosexual development and, in most cases, it is adaptive.