I'm lazy and don't feel like looking up my post from the past (it may have gotten lost in the big crash several years ago) but a fertilized egg is a unique living human being.
It conducts the seven process needed to be considered living.
It has its own unique DNA sequence. During development of eggs and sperm (meiosis), the chromosomes, one from your dad and one from your mom, "cross over" and exchange portions of DNA.