chemical messengers from the brain called luteinizing hormone (LH) and follicle stimulating hormone (FSH). In early puberty, LH tells the tubules to start producing sperm, which then move to the coiled tube at the back of the testicles, the epididymis. There they gain a tail and learn to swim straight. Sperm hang out in the epididymis until you’re ready for shooting (meaning ejaculation) because they are sensitive to heat and thrive in a temperature several degrees lower than the human body. That’s why you were designed with your scrotum hanging outside: to keep your testes cool.
Find out more about this book:YOU: The Owner's Manual for Teens: A Guide to a Healthy Body and Happy Life