Spermatogenesis is the process of formation of mature male gametes, the sperm cells from male germ cells.
Primary spermatocyte is a diploid cell that has derived from a spermatogonium. It undergoes meiosis, to divide into two haploid cells. These haploid cells are called secondary spermatocytes. Each secondary spermatocyte contains 23 chromosomes whereas primary spermatocyte contains 46 chromosomes.