I built my children out of whatever my wife was eating + a bit of material on my part.

How something came into existence shouldn't determine if its intelligence deserves protecting. Creating intelligent machines and torturing them, for instance, should definitely be a criminal act.

And if brain scanning/emulation catches up enough, then what? It's OK to torture a non-human intelligence if the source wasn't a brain scan? What if we start building our own out of composites or scratch?

Intelligence/capacity for suffering should be the deciding factor here. (And hopefully they'll breed more stupid animals for meat, until it's feasible to grow meat directly.)