Examiners at the European Patent Office (EPO) have refused to grant a patent for primate embryonic stem cells to the Wisconsin Alumni Research Foundation, on the grounds that the claims are applicable to human embryonic stem cells, which are specifically excluded from patentability in Europe.

Because the methods would require the use of a human embryo as starting material, or as a source for the starting material, the invention is considered contrary to morality. Although the applicant argued that the invention does not concern, or have as its object, the use of a human embryo, this was rejected by the EPO. The applicant also argued that as the morality rule does not apply to methods useful for therapy or diagnosis carried out on a human embryo, the invention could be of benefit to an embryo and therefore was not excluded from patentability. However, the EPO did not accept that the methods serve any useful purpose to a human embryo. Furthermore, it was argued that the interpretation of the morality rule was incorrect, because, taken to the limit, all downstream products that were isolated or derived from embryonic tissues would be excluded from patentability. But as these products can be generated by methods that do not require the direct and unavoidable use of a human embryo, the EPO rejected this argument too.

Because the methods would require the use of a human embryo as a starting material, or as a source for the starting material, the invention is considered contrary to morality.

James Thomson, a researcher at the University of Wisconsin at Madison, invented a method to isolate primate embryonic stem cell lines in 1995 and was issued US patent 5,843,780 in 1996. The patent covers claims on purification methods used to prepare stem cells for laboratory growth, as well as methods for obtaining and maintaining them. Geron paid for the university's research and received commercial rights to develop five embryonic stem cell lines owned by the university.