One of the many pro-abortion arguments has to do with "human potential" meaning that it is impossible to determine when a human being becomes a human being. It is inevitably human at the time of birth, but before then it only has a potential of becoming human, so until we are not sure what it is that is growing inside the mother's womb, it is okay to let the mother decide what she wants to do with it.
First of all, let's define what a human being is. A being is "the state or quality of having existence." And existence is defined by only one word: LIFE. Life is: "the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally". A foetus (and an embryo, too) is growing, developing, it is developing reproductive organs which are fully developed by the age of 16-18. So I am confident that it is alive.
Biologists classify human beings as Homo sapiens, a primate species of mammal. And since two individuals of the same species can only produce an offspring of the same species, the offspring of 2 homo sapiens individuals can only be a homo sapiens. Human.
At the moment of conception when the sperm penetrates the egg, changes occur in the protein coating around it to prevent other sperm from entering. At the moment of fertilization, the baby's genetic make-up is complete, including its sex. It own, unique genetic code is different from both father and mother. It is an individual.
Even if we know all this and still say that it is only potentially human, then think about this: when a human baby is born, it is inevitable that it is developing into a full-grown human being and we do everything in our power to make sure that this individual is safe, we protect it in order to give it the best chance to reach adulthood. You can say that a baby is only a potential adult, well, infancy is just a stage of human development just like toddlerhood or adolescence. But even thought it is only potentially an adult, nobody is questionning its right to life. We have no right to stand in its way of development, its body is its own, terminating its life is a serious crime.
Let's look at a foetus. It is inevitable that it is developing into a infant. Preventing it from becoming an infant is preventing the development of a human adult. The foetal stage is just as important to becoming a grown adult as adolescence. You can't even say that it is different from a child outside the womb because you can't see it. With the help of technology, you CAN see it (if somebody still needs proof of its existence).
So even if we see a foetus only as a potential human, we don't have the right to prevent it from reaching its "full potential", what's more it is our duty to protect it the best we can.
But if we know it is inevitably a human being (which I think everybody knows who opens their mind just a little bit), let's not be afraid of calling it what it actually is: MURDER