Sperm migrate through uterine contractions and the energies of its flagella to the uterine tube. In sperm motility, reverse peristalsis is engaged in the uterus and uterine tubes. For a sperm cell to fertilize an egg, it takes approximately 24 hours. The surface of the egg changes as the sperm penetrates the egg, therefore no sperm is allowed within. The kid is fully genetic, including whether it's a boy or a girl at the time of fertilization. Until they are trained it is difficult for sperm to be working.
