Some are asexual, and thus don't really have gender, they might be seen as female since they would bear similarity to females of sexually reproducing species but it isn't the same and they likely would not have the roles and behaviors associated with gender.

Some do have gender and are sexually monomorphic, meaning they look the same and develop the same regardless of their sex/gender, only difference is their reproductive organs.

Then there are ones that are sexually dimorphic and have great differences between the sexes and how the develop, differences such as size and strength, or colored markings, or both.

Out of these only the last one would benefit from hormones, and even then it would depend on species.

All of this assumes that Magic or shapeshifting isn't on the table, if it is this all goes out the window because they're no longer restricted to how their bodies are formed and basically have full control of the gender, sex, and species they choose to present as. Most of the stories I've seen the dragons have either full or limited shapeshifting abilities.