The article is based on the results of a comparative legal study of the status and protection of extracorporeal embryos in a number of European and non-European countries. In this context, the study also deals with the extent to which in vitro embryos can be created and/or used for research purposes (especially for stem cell research). The results show a considerable divergence with regard to existing solutions. This divergence is not due solely to different concepts of protection but is also an indication of the controversial debate on whether such entities are worthy of protection and, if so, to what degree it should be granted. The discussion indeed begins at the level of terminology where the attribute(s) characterizing an "embryo" in the legal sense are-already and seemingly without deeper meaning-anything but uniform. The reasons for this disparity, such as the time factor (which stages of development must have taken place after fertilization of an egg cell by a sperm cell?) or the method of genesis itself (aside from conception, which other methods are used to generate embryos?), could be particularly relevant. The differences mentioned lead, in turn, to the question of which legal consequences researchers must keep in mind especially regarding the risk of criminal liability-when engaging in international cooperation efforts with peers from more permissive countries.
