Testosterone is a male sex hormone that is important for sexual and reproductive development. The National Institutes of Health regards testosterone as the most important male hormone.Women also produce testosterone, but at lower levels than men.Testosterone belongs to a class of male hormones called androgens, which are sometimes called steroids or anabolic steroids.In men, testosterone is produced mainly in the testes, with a small amount made in the adrenal glands. The brain's hypothalamus and pituitary gland control testosterone production.he National Institutes of Health regards testosterone as the most important male hormone. Women also produce testosterone, but at lower levels than men. Testosterone belongs to a class of male hormones called androgens, which are sometimes called steroids or anabolic steroids.