The paper outlines the contemporary discussionon the impact of the new developments in bioethics and in biomedicine have on the concepts of human being and person. It also presents various definitions of the concepts. One of the most pressing bioethical and juridical issues is the moral and legal status of the unborn, closely related to the question, if the human being in his/her various developmental stages can be considered a person. Further, the paper examines the concepts of human dignity and the dignity of a person, which are seen as the sources of human, as well as individual rights. Attention is paid also to the polemic between Christian and Kantian approaches to human being as contrasted to the approaches rejecting these concepts as non-scientific. Another dilemma focused by the paper is the conflict between legal formalism on one side and the experimentalism of sciences and some philosophical conception on the other side. The paper examines also the possible using the scientific knowledge in the sphere of law, the crucial question being: Who is to be considered a human being? And who a person?