A simple science fact that everyone learned in high school biology class, but one which people continue to pretend isn't the case.
"The Court has treated the question of when human life begins as a matter of opinion...."
And since most jurists and liberals claim that we "can't really be sure", why wouldn't we error on the side of the unique human being? Could it be that we don't really value human life? Or perhaps we just value convenience more?
Bingo!
Today, the enlightened form of child sacrifice takes place in an abortion clinic, to the "god of convenience".