I'm not sure what you're asking me.... Is this supposed to be two questions?
The geckos may not breed because one may be infertile or the other just may not want to breed. You may have a hot female or cold male. Try putting the male with a different female to determine if it's the male or female not wanting or able to breed.
If you're also asking about bearded dragons, what exactly is the question? It could be the same situation.
There could be many reasons why they are not mating. You haven't given enough information to answer the question. Plus, I'm not really sure what the question is.