ing is important both for the center of an ethical relationship and for the boundary question of how far ethical obligation is to extend. It is the purpose of the present paper to attack the issue by dealing specifically with the boundary problem at the point of the beginning of individual human life. Many of the observations to be presented, however, can be generalized to other situations, both at the boundary and at the center, and may be persuasive even to those who may differ from the particular conclusions reached below. The lower boundary of human life means, most concretely, the question of the legitimacy of voluntarily induced abortion. This problem has received so far very little attention from American theologians. While these lines are being written, Joseph Fletcher has appeared in print with his support of the principle-which can only be a tentative one within his open system-that "nobody should be compelled to bear a child against her will."' He evidently ssumes that the fetus is not a fully human being, but he does not develop or support this thesis in detail. Yet, even in his system, the question "Who is my neighbor?" is admittedly a central and crucial one,2 as it is perhaps in any theological ethic. In any case, an exploration of the nature of human life is relevant for the ethics of abortion.