Originally Posted by
KageTokage
The Miqo'te race is noted as being genetically inclined towards producing more females then males, though they don't seem outstandingly rare since there's a decent number of male Miqo'te NPCs out and about.
As far as I can recall male Viera weren't noted as being rarer then females, though in the original Ivalice lore they were said to live in their own communities separate from the females, so it wouldn't surprise me if that ended up being integrated into XIV's lore. All that was really said about them thus far is that the adult males take other males into their care once they're of age and are very elusive, avoiding contact with basically everyone outside of when they occasionally visit female settlements to sire children.
We see a good number of female Viera in mixed race settlements on the First, so I'd assume the same probably holds true for some places on the Source and if they were willing to abandon their traditional ways for a more conventional lifestyle, I'd think some males would probably follow suit as well.