In total utilitarianism, it is a morally neutral act to kill someone (in a painless and unexpected manner) and creating/giving birth to another being of comparable happiness (or preference satisfaction or welfare).

Just wanted to note that this is too strong a statement. There is no requirement for the 1:1 ratio in "total utilitarianism". You end up with the "repugnant conclusion" to the Parfit's "mere addition" argument as long as this ratio is finite (known as "birth-death asymmetry"). For example, one may argue that killing 1 person to save 5 equally happy people is wrong, because killing is wrong, but as long as there is a ratio they would agree with (or, more generally, an equivalent number of saved people for each number of killed people), the repugnant conclusion argument still goes through.