Boys suddenly have sexual desire, want to have sex, may be related to the following aspects of the reasons: 1, by the body androgen level changes. Boys in puberty androgen secretion in the body is strong, especially in the early morning of the day, the body’s androgen level peaks, and thus the libido will be enhanced, there may be a sudden want of the situation; 2, the glans is more sensitive. Boys in puberty, due to the continuous growth of the genitals, the glans will be relatively more sensitive, if the underpants or pants worn by the tight, or other stimulation of the private parts, etc., will also suddenly trigger the libido, wanting to feel; 3, stimulated by the content of the sex-related. If the boys in the near future read books and magazines related to sexual content, film and television, etc., may also stimulate the boys’ sexual desire, so that it produces a sudden feeling of want.