Why is abortion right or wrong?

A pre-born child isn't "potential" anything. He/she is a human being. He/she does have a beating heart by the time his/her mother knows she is pregnant. And that heart is pumping his/her blood, not the mother's blood. A sperm or egg is a cell of the father or mother's body. Once they combine, the resulting cell is not the father's cell or the mother's cell. It is the first cell of their son or daughter's body.