(Click the link to comment and to vote – voting not working through email, sorry!)

A 3 week old female infant presents with a palpable inguinal mass of 2 hours duration. The dad states he noticed it while changing her diaper. He has seen it before while bathing her, but by the end of the bath it had disappeared. She is otherwise well, feeding and growing well, not vomiting, and is afebrile. She appears comfortable. The mass is nontender, and there is no overlying redness or discoloration. 

What is the most appropriate next step?