A hydrocele is a relatively routine testicular condition in which a sac of fluid is formed in the thin sheath that surrounds a testicle, causing swelling in the scrotum. Millions of men have had one at some point; at least 5 percent of male babies are born with them, according to the Mayo Clinic.

Generally, the condition is not too serious. Hydroceles are often painless and go away on their own. Sometimes, however, they can cause discomfort to the point where surgical intervention is required. Plus, a hydrocele may be an indication of something more threatening to your health.

Let's take a look at what hydroceles are, how they form, the different types and when you should seek the advice of a doctor.

How do hydroceles develop?

When a male fetus is near the end of his gestational term, the testicles descend from inside the abdomen into the scrotum