Assigning the property "you" to a zygote requires religion or some other kind of mysticism. There is no logic there. Quite often, zygotes never attach to become embryos. Embryos may not develop into a fetus. Just natural occurrences in life that the woman may not ever even be aware of. It often looks quite similar to the normal monthly cycle when it passes out and doesn't look any different. These are also abortion, just not medically induced. It wasn't until quite recently in history that people, under the guise of religion, decided that a zygote was a "you" and should get any kind of rights. Of course it is absurd and doesn't result in any positive outcomes

Most mammals, and indeed for the majority of humans (pretty much all humans until recent history), consider life to begin and end with breath. When we take our first breath and give our last breath

Romantically, the heart has been linked to various properties of our spirits. This has no logical connection to our actual hearts, of course. That romantic connection has been used to manipulate religious believers into supporting restrictions on human rights - the rights of living, breathing, existing humans

How else do you arrive at giving zygotes the assignment "you"?