Story of human life begins at moment of conception

IN HIS letter (November 17), Con Hayes argues that a full human person is not present until long after the early embryo stage in human development and it is therefore ethically permissible to kill the human embryo to further biomedical research.

I disagree entirely. To answer the question as to when human life begins, we must consult biology, the science of life.

Biology clearly tells us full human life begins at conception with the formation of a genetically complete, self-directing human entity, the embryo.