A new human being is created at conception

From the instant the male gamete (sperm) fuses with the female gamete (egg), a unique human being with his or her own DNA, different from those of his mother and father, is present. After fertilization, there are 46 chromosomes (or 47 in the case of Down Syndrome) where there were two sets of 23 chromosomes before. The resulting being is genetically human and alive, and therefore, by standard biological definition, a human being. From fertilization to natural death, there exists an unbroken and smooth continuum of human development during which the person needs only oxygen, water, and nutrients to live and develop physically.