Egg and sperm cells (the gametes) are different to the somatic(body ) cells. The somatic cells have 46 chromosomes but the gametes only have half that number(23) and are called haploid cells. Meiosis is a special type of cell division that halves the chromosome number so that when egg and sperm meet the full diploid number is restored. It is this Diploid number that triggers the fertilised ovum to start dividing by MITOSIS. MEIOSIS also causes the parental chromosomes to swap material . Called crossing over or recombination. That is why we are ALL unique. Because all the ova and sperm are unique. Hope this helps!
