Since ages FBS, fetal bovine serum (sometimes referred to as FCS, fetal calf serum) has been used in laboratories around the world. But more and more people question the use of FBS for different reasons, one of which being the ethical aspect.

Not everyone seems to know how serum is “harvested” and hardly anyone saw pictures from the actual process. This is a reason already to seek an alternative. With a synthetic serum replacement this is of course not the issue.

Further there are governmental directives like in the EU: The European Union has various directives on the use of animals and their well being. One of these is to minimize use of animals: if unnecessary they should not be used. Our knowledge of animals' welfare requirements has increased since 1986 (first directive). It does not include ethical reviews or requirements to obtain authorizations for experiments. 

The EU directive does not explicitly address the internationally recognized Three R concept of Replacement, Reduction and Refinement (Russel and Burch 1959) to minimize the use of experimental animals. Since upholding animal welfare is now integrated in the EU Treaties this must be taken into account in all policy areas.