The sperm and egg have 1/2 the amount because when the sperm fertilizes the egg, it equals out to the regular amount of chromosomes. That is why we have half chromosomes from our dad and half chromosomes from our mom, equaling out to normal amount of chromosomes.
It makes sense to me that that Sperm and Egg cels have only half the amount of chromosomes than a normal cell because, you get equal chromosomes from when they come together. so you get equal amount of traits from both sides.
