What's your opinion on the matter. That's what I'm really interested in, I can look up legal or religious definitions myself.
Except that
is my opinion; my culture has collectively decided to grant certain rights and privileges over time on the basis of age of the human. It has decided to grant what you're calling "basic human rights" at birth and others at later time periods. This is wise and practical, if not necessary to organize contemporary human societies. What I find problematic about my society's organization of its rights language is an unacceptable lack of consideration for anything that isn't human. It is as foolish as it is sickening.
However, we must not forget that we make up these self-limiting rules to govern ourselves and that fundamentally, there are no "rights" for any aspect of reality, human or otherwise. I personally dislike "rights" language for that reason – I much prefer descriptively objective language that outlines what something is capable of, not what it is "supposed to" use such capabilities for. The "rights" possessed by any aspect of reality are those things it has the power to do. Nothing more, nothing less. All else is a social construct and self-imposed limitation or tradition.
And for everyone, once an organism becomes a living person from your perspective, what, if any rights should they be granted, and why or why not?
They will be granted whatever rights the human culture deems beneficial for that particular time, or circumstance. Whether or not they
should do so is irrelevant, because this is what
will happen. And, for the most part, I don't disagree with the current rights granted by my culture at various stages of human development.
Given human overpopulation, I think it is an extremely foolish idea to extend rights my culture grants at birth to a human before it is born. This policy only makes sense when a species is endangered.