Fertilization marks the beginning of the biological life of an individual member of our human species. At fertilization the life of a new, unique, living human organism (i.e., a human being) begins.
See below for academic and peer-reviewed scientific literature affirming this proven biological truth. See On the Nightstand for additional recommended reading on human life in its first stages.Condic-Sources-Embryology
Life Begins at Fertilization: The following references illustrate the fact that a new human embryo, the starting point for a human life, comes into existence with the formation of the one-celled zygote.https://www.princeton.edu/~prolife/articles/embryoquotes2.html