In order for the sexual function to begin in men, sexual desire is necessary. Usually, sexual desire in men becomes apparent as an impulse and is accompanied by sexual thoughts and fantasies. However, recent studies have shown that the sexual function can be triggered, without the necessary pre-existence of sexual impulses, as long as there is intent on the part of a male to allow himself to be taken by the sexual stimuli, in order to enjoy himself. The idea that men are always in the mood to have sex is clearly a myth. Low levels of testosterone, stress or symptoms of depression, unpleasant previous sexual experiences or even feelings of fatigue, are often factors that inhibit sexual desire. However, desire alone is not enough to spark sexual function, because sexual stimuli are equally important.