When you’re on the go and you have to go, a public restroom is where you head. For millions, though, that’s not an option. It’s a place where peeing seems physically impossible.

That’s because being near other people causes your sphincter muscles to lock up. Those muscles control the flow of urine from your bladder. Once they freeze up, you simply can’t pee. It can happen in a public restroom, a bathroom in someone else’s home, and even in your own place if other folks are nearby.

As many as 20 million Americans have this problem. It’s known as shy or bashful bladder syndrome. Your doctor may call it by its official name, paruresis.

Without treatment, it can affect your personal, social, and professional life. You might find it hard to be away from home for more than a short time. You could end up avoiding parties, sporting events, and dates. It might even limit your choice of jobs. But you can get it under control with therapy.