The "prune belly" syndrome (PBS) combines malformation of the deferent urinary tract with cryptorchism and hypoplasia or aplasia of the abdominal musculature. Recent investigations have ascertained the role of urethral atresia or temporary urethral stenosis in the pathogenesis of PBS. The present case is classified as PBS combined with female pseudohermaphroditism and urethral atresia in a Potter syndrome. Of paradigmatic significance for the understanding of PBS pathogenesis, the case illustrates the almost exclusive occurrence of the syndrome in males, explained by the complex evolution of the phallic urethra. Hypoplasia of abdominal muscles is seen as a sequel to the extreme occupation of intraabdominal space. An alternative concept, assuming general defects in mesenchymal development that provoke independent, isolated malformations eventually subsumed under the term prune belly syndrome, is discussed in this context.