To Bladeslap   

"How about Abortion, a large part of the country justifes killing humans by claiming it's not human yet!"

I think you mischaracterize the issue, or are quoting somebody who mischaracterize it. The issue isn't that an abortion terminates a human, it's whether the mother's right to control her body. At some point the rights of the unborn person must be protected. Exactly when does the zygote become a person? Many religions make that very late in the process, up to a year after birth. Nobody in America is presenting that standard, but some believe that before the actual birth, abortion is available. To me, that is irrational buit that is one of the two extremes in the abortion issue.

You present the irrational flip side of the same coin as justified, so how do you know that? Religious convictions  do not count as many other faiths have beliefs that argue against yours- and America is founded on the principle that faith is an issue for the individual, not the state.
 

It is an absurd simplification to assert that a 2-celled zygote is a 'person'. It has none of the characteristics of personhood other than DNA. That standard makes surgery a murder in removing any tissue identifiable by genetics as a "person". Enlightenment principles don't make your warts into people.