Speedo resized their small Endurance suits to fit girls, but the new youth sizing is very different.  My daughter normally wears a 24, but the Youth Endurance in a 24 is cut way too small in the rear end.  We even tried a Youth Endurance 26 and it is cut too small as well.  My daughter is very slender, so beware when you order the smaller sizes that the cut is way different.