Since 2012, stem cells and stem cell products are defined as ATMP (advanced therapy medicinal products) and/or tissue preparations in many countries and have been subject to the respective drug legislation to ensure their safe application. In Germany they are subject to the Medicinal Products Act (Arzneimittelgesetz) and everyone who manufactures or processes them is required to be licensed to do so. In countries where a license is not necessary, treatment with stem cells is considered to be significantly less safe.