Besides extremists, a majority of people are both pro-life and pro-choice to some extent, because we all value human life. In the abortion debate, we should first define what is the "unborn" before we answer the question whether or not it is morally and legally reasonable to destroy and kill it. If abortion was similar to pulling a tooth or clipping a fingernail, I would see no reason to oppose it or limit the individual's right on this matter. The main question in the issue of abortion is what is killed in abortion, and this leads to the conclusion whether abortion is ethical or not.
Based on the science of embryology, every embryo is a distinct living and whole human being since the earliest stages of development. Based on Keith Moore's book "The Developing Human: Clinically Oriented Embryology", the beginning of the human development is described as "human development begins at fertilization when a male gamete (sperm) unites with a female gamete (oocyte) to form a single cell called a zygote. This highly specialized, totipotent cell marked the beginning of each of us as a unique individual." (Moore, 2003). In "Langman's Medical Embryology", Thomas Sadler defines the beginning of the human development as "the development of human being begins with fertilization, a process by which the sperm from the male, and the oocyte from the female, unite to give rise to a new organism, the zygote." (Sadler, 2006).
There are other embryology textbooks agreeing that life starts at conception, therefore we can conclude that the beginning of life is no longer a matter of philosophical or theological discussion, but it is a well-known scientific fact. The purpose of life might be open to debate by philosophers and theologians, but scientifically conception is known as the beginning of human life. However it might be complicated for many people to consider a group of cells as a human.
