Some people should not have been born; and as there are other people whose existence is a good thing, we may say of the that they, in the same sense, “should have been born”; though of course they were, and it is not a point of much practical importance so far as it concerns the individual the desirability of whose birth is in question. Hitler should not have been born, Churchill should have been born, and there are other cases where it is debatable—though I admit that all such questions, are, as we say, “merely theoretical”. What I am claiming is that, if we regard ‘Hitler’ and ‘Churchill’ as proper names, Hitler’s mother and Churchill’s mother could not have presented themselves, prior to their conception, with sensible questions of the form, “ought we to give birth to Hitler?”, “Ought we to give birth to Churchill?” The latter appear to be parallel to, “ought I to spank Adolph?”, “Ought I to spank Winston?”; but they plainly are not.

Jan Narveson, ‘Utilitarianism and Future Generations’, Mind, vol. 76, no. 301 (January, 1967), p. 64