It has nothing to do with religion, or with religious beliefs, but it seems rather strange that a human would have such a callous attitude towards a developing member of the same species.
I would ask them what they think the embryo is. A dog? A sheep? An animal? A plant? No. Of course not.
Something non-living? Obviously not.
If it’s living, then what kind of a living creature is it? Animal? Plant? Extra-terrestrial? Human?
Let’s face it. There’s no getting round the FACT that, regardless of the nomenclature - zygote, embryo, fetus, baby - IT IS HUMAN AND IT IS ALIVE.