One common way to think about utilitarianism is to say that each person has a utility function and whatever utilitarian theory you subscribe to somehow aggregates these utility functions. My question, more-or-less, is whether an aggregating function exists that says that (assuming no impact on other sentient beings) the birth of a sentient being is neutral. My other question is whether such a function exists where the birth of the being in question is neutral if and only if that sentient being would have positive utility.

EDIT: I do recall that a similar-seeming post: http://lesswrong.com/lw/l53/introducing_corrigibility_an_fai_research_subfield/