Why in meiosis do the cells come out different from each other?

Each chromosome has two strands of DNA. One strand comes from the Father and one comes from the Mother. These two strands will be different. During meiosis only one strand from each chromosome is donated to each new cell. There are 2 to the power x different ways of donating chromosomes (where x is the total number of chromosomes). In addition, there can be a cross-over between the two different strands during copying. This means some of the genetic material on the ends of the chromosomes is exchanged between the strands. This increases the number of possible cells even more.