Abortion
Abortion is a form of murder because it takes the life of an innocent human being.
The Facts of Life
At conception, we become ourselves both by the action of biology and by God's sovereign action in giving the soul (the form of the body) spiritual powers: intelligence, free will, and immortality.
The human person is not just a byproduct of complex forms of matter; the human person is created directly and personally by God at the moment of our conception.
The zygote possesses its own DNA distinct from both parents. It has its own bodily identity and life. If it was not alive, it would not develop into a morula (sixteen cells) and then a blastocyst, which consists of the cells that will become the placenta and the cells that will become the embryo.
If the embryo does not have its own life, it would not continue developing within the mother's womb. It would be a miscarriage and no abortion would be needed.
The new being is alive.
The new living being is unquestionably human. It is not a dog, a giraffe, an elephant, or a platypus.
The new human being has its own genetic identity from the first cell (the zygote) to the last nucleated cell developed by its body before death.
The placenta is created by the blastocyst and embryo; it is not part of the mother's body--no part of the baby's body is part of the mother's body. The mother's body is identifiable by her genetic signature and the baby's body is identifiable by its own genetic signature.
All of this is basic biology. It is a matter of fact. One need not turn to revelation to discover that the child is a unique, living, human being who possesses the same rights as all other human beings: "the right to life, liberty, and the pursuit of happiness."