This fails to fit the spirit of the problem, because it takes the preferences of currently living beings (the childless couple) into account.
A scenario that would capture the spirit of the problem is:
"Eve kills a moderately happy hermit who moderately prefers being alive, uses the money to create a child who is predisposed to be extremely happy as a hermit. She leaves the child on the island to live life as an extremely happy hermit who extremely prefers being alive." (The "hermit" portion of the problem is unnecessary now - you can replace hermit with "family" or "society" if you want.)
Compare with...
"Eve must choose between creating a moderately happy hermit who moderately prefers being alive OR an extremely happy hermit who extremely prefers being alive." (Again, hermit / family / society are interchangeable)
and
"Eve must choose between kliling a moderately happy hermit who moderately prefers being alive OR killing an extremely happy hermit who extremely prefers being alive."
Haven't had one of these for awhile. This thread is for questions or comments that you've felt silly about not knowing/understanding. Let's try to exchange info that seems obvious, knowing that due to the illusion of transparency it really isn't so obvious!