The argument presented here is secular, scientific. The Christian argument is a dogma-based argument. In other words, some Christians regard their Church’s teachings as fact, as the Rule of God, beyond refutation. There is no appeal to reasoning and evidence, since the necessity to obey God transcends all else in life. The dogma is that human life runs from conception to final death.

Also, from a Christian perspective, what gives a human being value is its soul. The question then, if you want to try to reason or be empirical about it, is: "when does God put the soul in the body? And when does he take it out?" Given that lens, to say "life begins" at point x, y or z, you're second-guessing God. If I were worried about God's disfavor, I'd say conception is when God puts in the soul, because that is the most conservative reasonable choice. (Remember the Gospel according to Monty Python: "Every sperm is sacred, every sperm is great -- if a sperm is wasted, God gets quite irate.")