Yes. Umbilical hernias can occur in both children and adults.
Yes. Women who become pregnant. Men who develop beer bellies , anyone who does a lot of straining lifting. Smokers who cough a lot. Usually 40's to 50's they begin to show. Most often seen in adults though some babies may born with them. If painful or growing have it fixed. If stable for years and not painful , don't need to fix it. .