This is actually a great question that worries me. The ability of AI programming to model language and human understanding is pretty much here in terms of how real it can look. There will be people within a couple of years IMO that will "declare" some piece of AI to be conscious. The ability to interact with humans and mimic how humans act and what we say will be such that they will say "this level of self-awareness surpasses that of some children, and they're conscious, aren't they?" I have almost no doubt.