When the flourishing that personalist philosophy experienced at the beginning of this century came to an end, reflection upon the human subject faded into the background, or was overshadowed after the war by the rise of philosophies influenced by linguistics and those interested in societies rather than in individuals, such as Marxism. Thanks to the influence of different declarations in the Rights of Man, to the scientific contribution of American humanist psychology, and to the spectacular advances made in Bioethics in recent decades, the notion of personhood has again become an important subject for reflection. However, the classical concept of personhood that has been retained until now does not seem to correspond to the demands of biomedical ethics today. Will it not become obsolete as a result of the discoveries made in molecular biology?