Guys & Sexual Development: Male Reproductive Organs His male reproductive organ...know what he's dealing with How large is the average penis? The average size range of an erect penis is 5 –7 inches. But it can be anywhere from 4 –10 inches. How much semen is released during ejaculation? A normal ejaculation is about one teaspoon of semen. How many sperm are released during ejaculation? A normal ejaculation of semen could contain as many as 600 million sperm. Does male orgasm and ejaculation happen at the same time? Not necessarily. An ejaculation is caused by the muscles of the prostate gland pushing semen into the urethra. Male orgasm is a result of pelvic muscle contractions. What is premature ejaculation? Premature ejaculation is when a guy ejaculates before the penis penetrates the vagina, or just as penetration occurs. What's circumcision? Circumcision is a surgical procedure where the foreskin (a flap of skin covering the end of the penis) is cut away. A baby boy is usually circumcised soon after birth, for religious reasons or because it is believed to be important in keeping the penis clean. Is it important that the penis grows to a certain size during puberty? No. The size of the penis and testicles vary just as a man's height and shoe size differ. Starting to develop early or late doesn't affect the size of the fully-grown penis. What should a boy do if he has an embarrassing erection? During puberty, boys get a lot of erections for no apparent reason. Although it can be embarrassing, it's normal —and chances are , it's not that noticeable to other people. The best thing for a boy to do is to ignore the erection and concentrate on something else for a few minutes until it goes away. When do guys start to shave? For most boys, the first facial hairs appear between the ages of 14 and 16, but growth can begin even before a boy turns 13. Boys usually don't need to shave every day for the first year or so, when facial hair grows in only lightly. Learn about male reproductive organ and get helpful puberty information at BeingGirl.com.