Another topic many men wonder about—but are often afraid to discuss—is circumcision. Dr. Oz says the rate of circumcision in the United States has dropped from 90 percent to 57 percent in the last 40 years.
He says there are some reasons that circumcision makes sense—religious or family traditions, hygiene, and reduced risk of transmitting sexually transmitted diseases and viruses.
There are reasons to not circumcise as well. Some people consider it disfiguring, and doing it will reduce sensation during sex. "In a circumcised male, the bottom part, the underneath part of the penis, is the most sensitive part," Dr. Oz says, using a cucumber wrapped in a sock as a demonstration. "If you've not been circumcised, about half of the erogenous tissue on the penis is actually that foreskin area. Plus the foreskin covers over the glans—that front part, and that's the most sensitive part of the penis—so it doesn't get rubbed on, so it stays a little bit more preserved for when the foreskin eventually does pull back during intercourse."
The American Academy of Pediatrics doesn't take a position on circumcision. "They say it's up to you," Dr. Oz says.
For boys who haven't been circumcised, it is important to learn the proper way to clean themselves. Uncircumcised boys are 10 times more likely to get an infection than those who are circumcised, Dr. Oz says.
To do it correctly, "You pull the skin back and you can actually get under here and clean this corner out. Now these edges are where something called smegma resides, and that stuff can get pretty nasty if you don't clean it up," Dr. Oz says. "But here's the bigger issue—as a doctor I care about this. Most guys who are uncircumcised have the foreskin leading off. This touches the pants and it gets scarred after a while. It can get pretty taut. Sometimes it goes over the tip of the penis and squeezes down on it and that can actually strangle the tip of the penis. That's called a phimosis. When we see it, that's an emergency."