In my opinion, rights begin as soon as you can think, and end when you cannot think any longer.
What happens if someone is inadvertantly made unable to think during the course of his/her life? Do their rights suddenly come to an end? I could knock you out, or drug you, or anything else of the sort, and that in and of itself would be a violation of your rights, but would I then be allowed to do whatever I want to you?
And what is thought? Brain-activity? Consciousness? Electrical impulses that regulate the body?