It is a human being. It is very easy to get there. It is alive and it is a separate being. That's clear scientifically. Every being is a kind of being, and the law of biogenesis, which is a well-established law of science, says that every being reproduces after its own kind.
Human beings reproduce other human beings.
From the time this separate being comes into existence it is a human being and it is a human being throughout. The only thing that changes is what it look like. Whether real death is brain death or not, that may be a moot issue. Whatever it is, it is throughout. Clearly it is a being developing according to a certain pattern, and the pattern seems to be dictated by the kind of being that it is.