If a predisposition for the same autosomal recessive disease is found in both partners, this means a risk of 25% per pregnancy for the occurrence of this disease. The options depend on the timing of the test, the individual decision of the couple and the legal possibilities in the country. If the test is performed before pregnancy and the possibility of a serious genetic disease is detected: Preimplantation diagnosis is possible. In this case, the embryo is examined at an early cellular stage within the framework of in vitro fertilisation to determine whether the mutation is present in both copies of the gene. Only unaffected embryos are used. It is limited to severe diseases and must be approved in advance by an ethics committee in Spain. If the test is performed during pregnancy: The genetic material of the foetus is examined by prenatal testing for the presence of the disease.