According to an ethical theorem, initially developed by Kant in 1785, the complete instrumentalisation of human beings represents a violation of their dignity and is hence always ethically inadmissible. This is the case if a human being is used solely as a means to achieve an (external) end, without being respected as an end in himself or herself at the same time. This idea is also reflected in Article 1 (1) of the German Constitution. Critics consider the production of embryos for the sole purpose of achieving a pregnancy legitimate; all other possible purposes, e.g. research, would reduce the embryo to external factors and thus represent an unacceptable form of instrumentalisation. This argument may also be cited with regard to the selection of an HLA compatible embryo as a donor for a living sibling.

In contrast, supporters assert that the embryo is also implanted for its own sake. In addition, the fact that this is a possibility to help a seriously ill child should also be taken into account in the choice between conflicting rights; cf. Devolder 2005.