In T 315/03, the board observed that the relevant date for applying the test under R. 23d EPC 1973 (R. 28 EPC) was, as for all patentability criteria, the date of filing or priority. Nevertheless, evidence becoming available later could be taken into account, provided it related to the situation on that date.

In G 2/06, the Enlarged Board arrived at the same basic result. When assessing whether a claim contravenes R. 28(c) EPC, technical developments which became publicly available only after the filing date cannot be taken into consideration. Any other conclusion would lead to legal uncertainty, and risk being to the detriment of any third party who later provided an innocuous way to carry out the invention. The Enlarged Board thus concluded in the case before it that it is irrelevant that, after the filing date, the same products could be obtained without having recourse to a method necessarily involving the destruction of human embryos.