Life already began for the lucky sperm and ovum it fertiziled,that's when the NEW life began, as microscopic as it may be.
From that moment on there is a new life, quickly developing into different stages of development, existance, and eventually discontinuance, where nothing is living anymore.
At some point it can live without the assistance of the living host (mom) on the outside of the mom, totally independently from nurishment from the mom's body to its own, but not without someone(s) nourishing it once it is physically free from the mom...it still would die without that nourishment from other people. Eventually it develops enough to be able to go to the refirgerator to make itself a peanut butter and jelly sandwich.
So this new entity, created when a sperm fertilizes an egg, goes through a process of development continuing until it dies, maybe 70,80,100 or more years later, unless something happens in between.
It's rather impossible to set the moment it's life began at any other time than fertilization, in fact it's impossible.
Semantics has people playing games about the moment the new entity should be considered it 'began'.
We know when it began.
Everything after that are just points on a continum of developement....sorta like a 'life ruler', where conception is one end of the ruler and last breath is the other end..everything else in between can be measured by where in the development or dimise that life is at....at any given moment.
EVERYONE knows it didn't begin when it pops out of the mother, its been in there dancing and eating through a feeding tube gettin ready to make its grand appearance....kicking, burping, yawning, stretching and getting ready for it's big day.
I really never undersatood why people try to pinpoint some other moment to say it began.
Excuse me, I have to get ready to be born soon......oh you caught me sucking my thumb with that gizmo you're holding...move that outta the way when you see the top of my head, would you ??
EWWWW..who's going to clean up that mess on the floor, looks like a zygote bus accident`down there.
Accidents happen...that's how some of us GOT HERE !!!