A full-grown person is a “person,” and yet it’s still legal to kill that person under certain circumstances, such as self-defense.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
Of course it is. Our Constitution makes the distinction between innocent human life and those who are guilty of a capital crime.