Max Planck Institute for Foreign and International Criminal Law

A special supplement of the weekly journal Die Zeit as well as numerous other newspaper, radio, and television reports provided extensive coverage in 2007 and 2008 of a tragic case involving siblings who had fallen in love: Patrick S. and his sister Susan K., seven years younger and mildly mentally handicapped, grew up separately. He entered a home at the age of three and was then sent to live with an adoptive family. She was born after his departure and remained with her mother following her parents’ divorce. The two met in 2000, when Susan was 16 and Patrick 23 years old. Shortly thereafter, Patrick moved in with his mother and sister. Following the death of the mother a short time later, the siblings, who continued to live together, fell in love and had four children, two of whom are mildly handicapped. The three oldest children were removed from their parents by the Jugendamt (Youth Welfare Office). Patrick was convicted several times of the offense of sexual intercourse between relatives as defined in § 173 of the German Penal Code. The last conviction led to a sentence of two-and-a-half years’ imprisonment – the fact that he voluntarily underwent sterilization did not affect the sentence. After the judgment became final, his lawyer challenged the conviction of sexual intercourse between relatives before the Federal Constitutional Court and moved to have the criminal prohibition of sibling incest declared unconstitutional (§ 173 para. 2 sen. 2 German Penal Code).

This case was spectacular not only because of its human dimensions and numerous other circumstances but also because it raised explosive legal issues: What legal interest or interests does the statutory prohibition of incest protect? Religious values? Morality? Taboos? Family? Public health and/or genetics? Is the protection of these values by a secular criminal law legitimate, and is the criminal law equipped to fulfill these tasks? How are comparable cases dealt with in foreign criminal justice systems? How frequent is incestuous activity involving siblings? Is a criminal prohibition necessary at all if, as in some countries, incest remains taboo despite the absence of such a provision? These questions are explosive because they raise fundamental questions about the limits of a rationally justifiable criminal law.

The Max Planck Institute for Foreign and International Criminal Law has the necessary expertise to answer such questions, especially because of its focuses in the areas of comparative criminal law and criminology. Prof. Dr. Hans-Heinrich Jescheck, founder of the Institute, emphasized the close ties between these two areas by couching the Institute’s overarching goal in terms of uniting “criminal law and criminology under one roof.” The Federal Constitutional Court thus requested the Institute’s directors to prepare a joint expert opinion. This request did not include engaging in an assessment of the legal issue of the validity of the incest prohibition, which is within the exclusive province of the Constitutional Court; rather, the expert opinion involved answering an extensive list of questions on the comparative legal, criminological, eugenic, and medical bases of this legal issue.

The following researchers contributed country reports for analysis in the comparative legal expert opinion: