Does the drug have a medical use? If so what is it?

Since the discovery and synthesis of testosterone in the 1930s, anabolic steroids have been used by physicians for many purposes, with varying degrees of success.

Bone marrow stimulation: For decades, anabolic steroids were the mainstay of therapy for hypoplastic anemias due to leukemia or kidney failure, especially aplastic anemia. Anabolic steroids have largely been replaced in this setting by synthetic protein hormones (such as epoetin alfa) that selectively stimulate growth of blood cell precursors.
Growth stimulation: Anabolic steroids can be used by pediatric endocrinologists to treat children with growth failure. However, the availability of synthetic growth hormone, which has fewer side effects, makes this a secondary treatment.
Stimulation of appetite and preservation and increase of muscle mass: Anabolic steroids have been given to people with chronic wasting conditions such as cancer and AIDS.
Induction of male puberty: Androgens are given to many boys distressed about extreme delay of puberty. Testosterone is now nearly the only androgen used for this purpose and has been shown to increase height, weight, and fat-free mass in boys with delayed puberty.
Testosterone enanthate has frequently been used as a male contraceptive and it is thought that in the near future it could be used as a safe, reliable, and reversible male contraceptive.
Anabolic steroids have been found in some studies to increase lean body mass and prevent bone loss in elderly men. However, a 2006 placebo-controlled trial of low-dose testosterone supplementation in elderly men with low levels of testosterone found no benefit on body composition, physical performance, insulin sensitivity, or quality of life.
Used in hormone replacement therapy for men with low levels of testosterone and is also effective in improving libido for elderly males.
Used to treat gender dysmorphia (the belief that one was born the wrong gender) by producing secondary male characteristics, such as a deeper voice, increased bone and muscle mass, facial hair, increased levels of red blood cells and clitoral enlargement in female-to-male patients.

http://en.wikipedia.org/wiki/Anabolic_steroid