Problem of the harmonization of philosophies for genotoxicity testing

Recently, Ashby (1993) published a paper on 'Precedents or possibilities: which should guide the harmonization of mutagenicity test protocols and carcinogen prediction strategies?'. Having been involved in two activities referred to by Ashby (Berlin Workshop "Current issues in genetic toxicology from the regulatory viewpoint" in conjunction with the 22nd EEMS meeting; development of an EC strategy for genotoxicity testing of new chemicals), I would like to give some further information and add my personal opinion on two aspects of Ashby's presentation. More transparency as to the background of different approaches might help to achieve harmonization.