As a result of current medical practice in this area, surplus embryos arise. In Ireland these embryos can be frozen, where after a period of some three to five years they will cease to be viable. Alternatively, they may be reinserted in the donor to be subsequently excreted. In certain other countries, the legal and ethical regime allows for the donation of such embryos for research. This approach was described, in the paper already referred to, by the Catholic University of Louvain in the following terms: