No, in ancient times they had no early means to confirm pregnancy, and quickening was one way that was relied upon. That religions used a similar benchmark is no surprise.
No, I am saying that there is no naturally occurring process that would make a liver become a unique human being.
Until age 3 or 4 it is unlikely any human could develop without the aid of an adult.
Bullshit. There are plenty of signs before 14 weeks. The word itself means alive.
http://en.wikipedia.org/wiki/Quickening#Legal_history
You moved the goalpost on the liver cell. Who said a natural process is important? Why would it be?
A born child is already developed as fully human. It has all the component parts and only needs time. While it may need some support, it is capable of living as a human in the environment of humans. A zygote is not.