An inguinal hernia is a protrusion of some of the contents of the tummy into the groin area. It is a common problem, particularly in boys, as there is an area of weakness or passage-way which originally allowed the testis to descend from the back of the tummy cavity into the scrotum. If this passage stays open, a loop of bowel can pass from the tummy cavity into the groin and sometimes even down to the scrotum. This is painful for the child and can damage both the testis and the bowel. In girls, a hernia may contain one of the ovaries and this may also be damaged whilst inside the hernia. An inguinal hernia should therefore always be repaired once it has been diagnosed, especially in children less than 12 months of age when the risk of the hernia becoming stuck is highest.