Urology is the branch in pediatrics that mostly deals with urinary-tract system in males and females.

Several common medical conditions will be discussed here, those which are more common off course.  

Chapters of pediatric urology

Inguinal hernia and hydrocele in children

Daytime wetting in children (diurnal enuresis)

Bed-wetting in children

Daytime urinary frequency of childhood

Meatal stenosis