<span>The male testes have tiny tubules containing diploid cells called spermatogonium that mature to become sperm. The basic function of spermatogenesis is to turn each one of the diploid spermatogonium into four haploid sperm cells.</span>
Twins form in one of two ways: Identical twins occur when a single fertilized egg splits into two. Fraternal twins occur when two, separate eggs are fertilized by two, separate sperm.