In process of meiosis. The hypothalamus or the master gland in most animals, including humans send signals to the ovaries and testes of the reproductive system. In response to these signals, these ovaries and testes undergoes thesex cells division which is called meiosis. Spermatogenesis in male gametes, is the process of sex cell division among sperm cells. On the other hand,oogenesis is for the female gametes. These cell divisions among respective gametes produces haploid cell which only contain one pair of chromosomes, in number -23.