If it's only when he is crying I don't know if it is serious enough to take him in, but then again, I'm far from well-versed in this matter. You should probably have him evaluated by a pediatrician to make sure that this is normal. Here is a link to Inguinal Hernais:
Inguinal Hernias
In infants, an inguinal hernia is most often caused by a protrusion of a loop or portion of intestine or a fold of membrane from the abdomen — or in girls, from an ovary or fallopian tube — through an opening into the groin (the area where the abdomen meets the top of the thigh). The opening is caused by the presence of a fold of the peritoneal membrane, which produces a sac. Within this sac, the loop of bowel can protrude.
The hernia is apparent as a bulge in the groin area, especially when the child cries, coughs, or stands.
Sometimes, in boys, the inguinal hernia extends beyond the groin into the scrotum (the sac that holds the testicles). In girls, it can extend to one of the outer labia (the larger lips of tissue around the vaginal opening). In these cases, an enlargement or swelling can be seen that extends from the groin into the scrotum or labium.
More common on the right side, inguinal hernias occur far more often in boys than girls and are most common in preemies, baby boys with undescended testicles, and kids with cystic fibrosis. Kids with a family history of hernias are also at risk.
Other conditions that may look like inguinal hernias, but are not:
* A communicating hydrocele is similar to a hernia, except that fluid causes the bulge rather than protruding tissue. Depending on its location, the hydrocele may be left to disappear in a year or two or it may be treated as a hernia — with surgery. In infants, the hydrocele may not require surgery, as many go away by the second birthday. Some can change size depending on how much fluid goes in and out, and some may appear bluish because the membrane that causes the hydrocele is blue.
* Occasionally, a retractile testicle (a testicle that retracts from the scrotum from time to time) causes a bulge in the groin area. It may not need treatment but should be evaluated by a pediatric specialist.
* A femoral hernia is rare in kids and can be confused with an inguinal hernia. It consists of tissues that have pushed in alongside an artery into the top of the thigh. It appears as a bulge at the top of the thigh, just below the groin.
http://kidshealth.org/parent/system/surgic
al/hernia.html
