The acceptance of prenatal diagnosis that may result in an abortion in cases of embryonic abnormality is not consistent with the rejection of preimplantation diagnosis if this rejection is justified by referring to the embryo’s dignity or the dignity of handicapped people. Abortion after a prenatal diagnosis may violate dignity even more because the embryo is already in a much more advanced state of development than the fertilised egg in vitro. One of the tasks of bioethics is to detect the standards in our moral, ethical and theoretical views and to analyse the reasons for accepting certain practices and for rejecting others. Inventions can only be threatening if they violate our goals and norms. So firstly we have to make sure what we really want in the long run and if there is a consensus about this. Secondly scientists have to operate in a way that is transparent for others.