At conception the life formed is unique and human. This is not subject for theological debate any more, this is science.
That is why when people want to excuse abortion they bring in the concept of "soul". Even if they will deny the existence of a soul in any other situation.
Souls are metaphysical. You can not see, weigh or measure a soul. Makes them very handy as an excuse when you want to deny a fellow human personhood.
Someone remarked that if an unborn baby isn’t a human, why is there a demand for their parts.