This is true and occurs mainly in sexual reproduction. In man, the male gamete (sperm) meets and the female gamete (ovum or egg) and fertilization occurs to produces what is called a zygote. Both sperm and ovum are haploid meaning each of them has only one complete set of chromosomes (23 pairs). The zygote formed is diploid meaning that it has two complete sets of chromosomes - 46 pairs. The zygote soon develops into an embryo, which develops into a baby.