In two unrelated families, there was familial occurrence of gastroschisis. In one family, a boy and girl were affected and there was a family history of stillbirth, abortion, prematurity, and esophageal obstruction. In the second family, two boys were affected and there was a family history of spontaneous abortion, inguinal hernia, and umbilical hernia. The recurrence of gastroschisis, generally considered a sporadic congenital effect, suggests that the condition may be genetic in nature. Furthermore, the pedigree of one of the families suggests that gastroschisis may be a severe expression of umbilical hernia or other abdominal wall defects. Autosomal dominant inheritance with variable expressivity or multifactorial inheritance may explain the occurrence of gastroschisis in the two families. Thus, a family history of abdominal wall defects may increase the risk for gastroschisis.