I guess I am willing to bite the bullet and say that, as long as entity X prefers existence to nonexistence, you have done it no harm by bringing it into being. I realize this generates a number of repulsive-sounding conclusions, e.g., it becomes ethical to create entities which will live, by our 21st century standards, horrific lives.

At least some of them will tell you they had rather not been born.

If one is willing to accept my reasoning above, I think one can take one more leap and say that statistically as long as the vast majority of these entities will prefer existing to never having been brought into being, we are in the clear.