It occurs to me that the various utility indifference approaches might be usable in population ethics.

One challenge for non-total utilitarians is how to deal with new beings. Some theories - average utilitarianism, for instance, or some other systems that use overall population utility - have no problem dealing with this. But many non-total utilitarians would like to see creating new beings as a strictly neutral act.

One way you could do this is by starting with a total utilitarian framework, but subtracting a certain amount of utility every time a new being B is brought into the world. In the spirit of utility indifference, we could subtract exactly the expected utility that we expect B to enjoy during their life.

This means that we should be indifferent as to whether B is brought into the world or not, but, once B is there, we should aim to increase B's utility. There are two problems with this. The first is that, strictly interpreted, we would also be indifferent to creating people with negative utility. This can be addressed by only doing the "utility correction" if B's expected utility is positive, thus preventing us from creating beings only to have them suffer.

The second problem is more serious. What about all the actions that we could do, ahead of time, in order to harm or benefit the new being? For instance, it would seem perverse to argue that buying a rattle for a child after they are born (or conceived) is an act of positive utility, whereas buying it before they were born (or conceived) would be a neutral act, since the increase in expected utility for the child is cancel out by the above process. Not only is it perverse, but it isn't timeless, and isn't stable under self modification.