Equal genetic contribution of male and female parents ensured in the progeny is ensured during sexual reproduction, where a unipoloid female gamete fuses with a uniploid male gamete to produce a zygote, which is diploid and gives rise to the progeny. The female gamete contais 23 chromosomes and the male gamete also contains 23 chromosomes. So the zygote that is formed contains a full normal set of 46 chromosomes.