in ∀V i talk about the plausible ethical unviability of human children.
but, there is a broader category of moral patient whose existence i believe must be prevented due to their ethical unviability. for example, a moral patient which strongly desires to suffer continuously and to modify itself in order to never change its mind about that, cannot exist without either their preferences being unreasonably dissatisfied or their existence generating too much suffering.
it might be that such a moral patient cannot coherently exist — but if it can, i still oppose letting it come into existence, due to this issue.
depending on your ethical framework and your valuing of various things, it may be that no, some, or all potential moral patients are unviable. figuring out who is, of course, an important question that might need figuring out.