The Life of a Human Being Begins at Conception

The life of a human being begins at fertilization (or conception), when a sperm cell fuses with an oocyte (egg) to produce a new human organism. This individual is called a zygote at the one-cell stage of development, an embryo through the first eight weeks, and a fetus from eight weeks until birth. Each of us was once a zygote, embryo, and fetus, just as we were once infants, toddlers, and adolescents. All of these terms refer to stages in the life of a member of the species Homo sapiens. Here