As far as sperm meets egg, I mean, I could just say the first step is attraction, penetration, when the egg successfully implants

But you can't and you know that. None of that is the moment when a developing singular new organism is formed.

Your point of view on conception and beginning of life is subjective, not objective.

No, it's not objective. There's a difference between a person and an organism. I'm not pro-lifer because I don't believe a human and a fetus are the same thing. But scientifically you can't say that conception isn't the beginning of a new life form. It is. It's just not fully developed yet. Whatever the Romans believed was out ignorance and spiritual beliefs. People are wrong to say conception is murder because it would imply that the organism is a fully developed human with thought rights and personhood. But you literally can't deny that a new living individual organism has formed that, assuming everything goes right, would eventually develop into an actual person and to me that is something serious.