The present invention relates to novel substituted steroid derivatives which represent selective inhibitors of the 17β-hydroxysteroid dehydrogenase type I (17β-HSD1) and, in addition, which may represent inhibitors of the steroid sulphatase, as well as to their salts, to pharmaceutical preparations containing these compounds and to processes for the preparation of these compounds. Furthermore, the invention concerns the therapeutic use of said novel substituted steroid derivatives, particularly their use in the treatment, inhibition, prophylaxis or prevention of steroid hormone dependent diseases or disorders, such as steroid hormone dependent diseases or disorders requiring the inhibition of 17β-hydroxysteroid dehydrogenase type I and/or steroid sulphatase enzymes and/or requiring the lowering of the endogenous 17β-estradiol concentration.