There is much to be said about steroids from the medical perspective.

Abuse

During the 1990s, anabolic steroid abuse became a national concern in the United States. These drugs are used illicitly by weight lifters, bodybuilders, shot putters, long distance runners, cyclists, professional baseball players and others to give them a competitive advantage and improve their physical appearance.

According to the 1999 Monitoring the Future Study, the percentage of eighth, tenth, and twelfth graders who reported using steroids at least once in their lives has increased steadily over the past four years (an average of 1.8 percent in 1996, 2.1 percent in 1997, 2.3 percent in 1998, and 2.8 percent in 1999). In addition, steroid use to enhance athletic performance is no longer limited to high school males; a 1998 Pennsylvania State University study found that 175,000 high school girls nationwide reported taking steroids at least once in their lifetime.

Concerns over a growing illicit market and prevalence of abuse combined with the possibility of harmful longterm effects of steroid use led the United States Congress in 1991 to place anabolic steroids into Schedule III of the Controlled Substances Act (CSA). The CSA defines anabolic steroids as any drug or hormonal substance chemically and pharmacologically related to testosterone (other than estrogens, progestins, and corticosteroids) that promotes muscle growth. Most illicit anabolic steroids are sold at gyms, competitions, and through mail operations. For the most part, these substances are smuggled into the United States. Anabolic steriods commonly encountered on the illicit market include: boldenone (Equipoise), ethlestrenol (Maxibolin), fluxoymesterone (Halotestin), methandriol, methandrostenolone (Dianabol), methyltestosterone, nandrolone (Durabolin, DecaDurabolin), oxandrolone (Anavar), oxymetholone (Anadrol), stanozolol (Winstrol), testosterone, and trenbolone (Finajet). In addition, a number of counterfeit products are sold as anabolic steroids.

Physical side effects include elevated blood pressure and cholesterol levels, severe acne, premature balding, reduced sexual function, and testiclular atrophy. In males, abnormal breast development (gynecomastia) can occur. In females, anabolic steroids have a masculinizing effect, resulting in more body hair, a deeper voice, smaller breasts, masculinized or enlarged clitoris, and fewer menstrual cycles. Several of these effects are irreversible. In adolescents, abuse of these agents may prematurely stop the lengthening of bones, resulting in stunted growth. Serious medical illness can result from external hormone use. Enlargement of the heart (the heart is a muscle and thus affected by the muscle-building qualities of the hormones) is a risk, which increases the chance of a cardiac event occuring in later life. Another major health risk is long-term liver damage, particularly if the anabolic steroid compound is 17-alpha-alkylated.

(cut'n'paste from http://www.dea.gov/concern/steroids.htm)