Celiac disease is a disorder where eating gluten, a type of protein found in wheat, barley and rye, causes the body's immune system to attack and damage the small intestine.
Researchers in Germany studied children and adolescents with intestinal problems, including Crohn's disease, ulcerative colitis and celiac disease. They found that 28 percent of the celiac children were born by Cesarean section, compared to no more than 19 percent of all other groups.
Doctors say many of the children's mothers may have had undiagnosed celiac disease, which can increase the risk of cesarean section.
The study is published online in the journal Pediatrics.