Current guidelines recommend the use of antiandrogenic medication in addition to psychotherapeutic procedures in the treatment of patients and sexual offenders with severe paraphilic disorders and a high to very high risk of committing severe sexual offences. This article provides an overview about the current state of research concerning the effectiveness and possible side effects of antiandrogens and discusses the legal and ethical basis of using antiandrogens in the therapy of paraphilic disorders with a focus on gonadotropin-releasing hormone (GnRH) agonists. Meanwhile, a great deal of empirical evidence exists with respect to the effectiveness of GnRH agonists for lowering paraphilic sexual fantasies and behaviors; however, GnRH agonist treatment also still has a risk of mild to severe undesired side effects, e. g. hypertension, hyperlipidemia, liver damage, bone demineralization and depression. Nevertheless, in German forensic psychiatric institutions a not insignificant proportion of patients are treated with antiandrogens and furthermore, in the last few years treatment with GnRH agonists has become more important. In Germany, GnRH agonists can only be used on a voluntary basis; however, in some European countries and North American states legal statutes for compulsory treatment also exist. This is clearly contrary to the recommendations of current international guidelines. In light of the fact that GnRH agonist treatment could violate basic human rights, the need for an ethically sound approach is even more important in the decision for therapy with GnRH agonists. This article provides some proposals for a treatment approach that is in line with current ethical and legal requirements.