It should be quite easy to determinate uroplatus spp. sexes. Males has large hemipenal bulges..
Some of the uroplatus spp. (like u. phantasticus, lineatus and henkelii) can be determinated by their appearances but not U. sikorae sikorae and U. sikorae sameiti.

The gecko should be atleast 6 months old before it can be sexed.. I think.