The concept of personal identity has recently come to play an increasingly important role in bioethical discussion concerning the beginning and end of human life. This study does not aim to represent the whole range of applications of theories of personal identity to bioethics. It focuses only on the beginning of human life, namely on the question of the moral acceptability of abortion. The author begins by describing an argument rejecting the acceptability of abortions which has been advanced by P. Lee, and it is shown that the validity of this argument depends on a certain conception of personal identity. Then the author briefly defines the psychological approach to personal identity, and he points to its weaknesses. There follows a discussion of the theory of animalism which claims that our persistence in time does not comprise any psychological factors. The conclusion of the article deals with various theories of moral status and indicates the inadequacy of functional criteria in accounting for the moral point of view. The article finishes by stating that the moral status of human beings should be founded on the concept of human dignity. If the considerations in the study have been set out correctly then they justify the following conclusion: abortions are morally unacceptable., David Černý., and Obsahuje poznámky a bibliografii