If you can prove this then we can claim its a part of the womans body. However even if it is a part of the womans body and proven with science it still is wrong in most situations to kill a lifeform.

It should not be something the woman decides on her own, she should get permission from an authority or doctor.

I'm against abortion unless its authorized by someone qualified to make decisions like this and not all women have the sense to make decisions like these just like not all people have enough sense not to use gun and shoot people.