Sex between the Races Lore?

[Telsyr]

Being able to breed does not make them the same species. The question is whether or not their children are fertile. If their children aren't fertile, they likely aren't the same species (but are very closely related, sort of like Horses and Donkeys, which can crossbreed - producing Mules - but their offspring are sterile).

That is only assuming that the biology laws of Eorzea work in the same way as they do in our universe. I think the best way to explain this situation is too look at other MMOs.

TERA for example, as it has been explained through lore and various cross-breed NPCS that, the child always takes the apperance of the mother in regards to what race/species it is while both parents contribute to the lesser genetic makeup (Hair color, eye color, skin color, etc.). Pokemon also works this way so whos to say Eorzea doesn't also work in this fashion? Atleast untill they actually explain where baby Lalgagyns come from..