<prompt> Most common cause of urinary obstruction in a male infant is:Anterior urethral valvesPosterior urethral valvesStoneStricture  <response>: Posterior urethral valve is the most common cause of urinary obstruction in a male infant. Urethral valves are mostly posteriorly located, anterior urethral valve are usually associated with congenital urethral diveiculum. Renal calculi and stricture are uncommon in children. Ref: Kliegman, Behrman, Jenson, Stanton 2008, Chapter 540, Obstruction of urinary tract, In the book, NELSON TEXTBOOK OF PEDIATRICS, Volume 2, 18th Edition, New Delhi, Pages 2235 ; O P Ghai Essential Pediatrics, 6th Edition, Page 467 