I dont consider there to be life until the baby has left its mother and is breathing on its own.
Okay, So I'm going to assume that you're against killing a person once they are alive, right? This means that we must be sure, without a doubt, that there is absolutely no life before a baby is born. If there is even a possibility of life, it would be wrong to destroy it. Take, for example, a group of construction workers about to demolish a building. Before destroying it, they must double (and even triple) check to make sure that there is no life at all inside the structure. They would never demolish a building if there were any chance of someone being inside.
Here is a list of quotes from both doctors and textbooks which say that human life begins at conception. Maureen L. Condic, a doctor of Neurobiology and a professor at University of Utah School of Medicine, concludes that life begins at conception. Here is her paper, titled "When Does Human Life Begin?" There are countless professional arguments which state that human life begins well before the birth of a child. Therefore, if we cannot be absolutely sure that birth is the beginning of life, why are we killing the child before then?
I should not be the one defending when life begins. Rather, you should be proving to me that there is absolutely no life before we destroy it.