What a great question! In a sense all organisms have been alive since life began in the primordial soup. Although as individuals each of us is conceived when a sperm fuses to an egg to form a single cell called a zygote, the sperm and egg were themselves alive and came from cells in a parent organism that was similarly conceived. So organisms do not really begin life at conception--that is just the creation of a new genetic identity from something that was already alive. Everything alive today is a continuation of a living process (cell division) that began on earth over 3 billion years ago. We are all related, descended from the same ancestral cell that emerged from the primordial soup way back when.