The scientific stages of fetal development are important for our analysis because many ethical discussions about abortion take into account such factors as the fetus’s heartbeat, its ability to feelpain, and its ability to survive outside the womb.the scientific labels given to the different stages offetal development do not, in themselves, help us reach ethical conclusions. But they provide a standard framework for any discussion of human development. In fact, the terms used to describe humanfetal development are used throughout the biological sciences and pertain to most if not all vertebrates.