Sexual function in humans is varied and complex! It is not always acted out by the body. It can happen purely in the imagination, or in other ways, for instance, in the arts or at work. Body sexual activity, on the other hand, involves the mind as well. In the body we need the endocrine system (body chemicals), neurological system (nerve supply), and musculo-skeletal system (muscles and bones ) to be in working order. In the mind, we need to feel safe and with somebody who is good for us. We need also to feel that sex is an OK thing to do, and nothing to be ashamed of.

Sexual interest, or libido, gives us the drive which leads to finding the partner and the opportunity for sexual activity.

Sexual activity starts with an idea, or feeling attracted. Next comes arousal, then orgasm. After this, in men, but not in women, there is a refractory period when no sexual activity can take place.