The German genetic engineering act gives an occasion to discuss public participation within the legal system. Participation is described as a consequence of failing political programming of the law – and especially as a consequence of failing externalization of decision risks. In spite of these intelligible social motives, participation itself causes irritations resulting from a dedifferentiation of social subsystems- for instance politics, economy, law, morals. Consequently the law will react on public participation by a closure of its discourse. Moral or political arguments will probably not be heard within the legal procedure. Taking into account, that the law will need further programming performance from other parts of the society, it seems to be advisable to study „round tables“, technology assessment and mediation procedures, and similar interfaces between law, science, and politics.