I initially thought they were both males as they were developing. I recently began thinking differently because one frog accounts for about 90% of the calls at night. He is also the one with the pinkish, swollen pads. The other doesn't call much and has pads, like both males and females do, but they aren't swollen and pink.
These are very hard to sex. Both males and females call, albeit males call more than females. Both males and females have nuptial pads, but males are larger, swollen, and pink.
The link below looks just like the frog I think is possibly a female. I thought this forum had some frog wizard capable of identifying the sex even without pictures?
*HELP* Mossy frog sexing *HELP*
Time will tell. I will try to get some pictures up. I am looking into getting some dart frogs now. Frogs are so cool.