You said it would be unethical for people to create a simulation wherein the simulated minds might experience suffering. If you have children, you are creating new lives that are capable of experiencing suffering, and who inevitably will at times.

So doesn't that also apply to the whole simulated universe as well?

Yes? Either I'm misunderstanding your comment, or we're just running in a circle now.

You said that "it would be unethical to create a simulation in which the simulated beings were sophisticated enough to be self-aware and capable of significant suffering", but it applies also to having children, so you clarified that the creator has to have a "reason to believe there was a sufficient likelihood of a sufficiently negative outcome" for it to be unethical. So if the creator of the universe doesn't have such reason, your original assumption is not valid anymore, making it perfectly ethical to create a simulation of universe as long as you believe that the net outcome will be positive.

Thank you. That's what I was getting at. A simulated world would contain suffering just as the 'real' (presumably) world does. Bringing 'conscious life' into a simulated world would be no more unethical than bringing life into the world we inhabit.