Sexing young bearded dragons (below 6-12 months of age) can be a little hit and miss if you've not had much experience at sexing them. Some dragons develop & mature later than others, and some are a little obese and it can be difficult to distinguish the fat from the appropriate bulges. Chances are, if you've identified a baby as being male, it's 99% certain that it's a male. If you've identified a baby as being female, it simply might not have developed yet, and a lot of the time, they ultimately end up being male.

Here are a couple of pictures to help you sex adult dragons.

Male Dragon - showing enlarged hemipenal bulges on the tailbase.

Female Dragon - Just a single bump in the center of the tailbase.

Hopefully this has cleared up some of your confusion. Remember, never house two males together no matter what their age. Even as babies, they can mature overnight and quickly turn on their cagemates.