When do you become a human being?

[Bengalzona]

When does someone graduate from being a sperm and an egg to a human being? At conception? At birth? Somewhere in between?

I'd like your opinions. And, if you wish to share, what guides your opinions.

Special Note: This can be a very contentious topic. I'm not looking to open a debate in this thread. I am just really interested in everyone expressing their opinion. Therefore, I ask that you not express your opinion on someone elses' opinion. Rather, just limit to expressing your opinion to the thread topic. Thank you in advance for your cooperation.