I dont really consider 4 months old juvies... but thats just me, im not quite sure at what age they are officially juvies, I should probably look that up. Usually they poop and urinate at the same time. It would be hard to guess that one is male and one is female at that age expecially. Do you have any pics? Unless of course you got them from a well experienced breeder and new what temps they were hatched at.