Due to the fact that women do not produce as much testosterone as males do, it is impossible for a woman to gain huge amounts of muscle mass. The image that may come to mind is of professional female body builders. Many of those women unfortunately use anabolic steroids along with other drugs in order to achieve that high degree of muscularity. In addition, most also have good genetics that enable them to gain muscle quickly when they spend hours in the gym lifting VERY HEAVY WEIGHTS. They do not look like that by accident. Women who weight train without the use of steroids get the firm and fit cellulite-free looking body that you see in most fitness shows these days.