I rather think, from what little I know of the lore, that they made these Viera genderlocked, for lore reasons, and brought in the furry race to even things out, for similar reasons. I doubt they will be bringing male versions anytime soon, if they are confirmed genderlocked. Only way I can see them bringing in male/female variants of either would be if there was enough community uproar for them. For Viera, let's just get this out of the way, it would have been 9/10 female to males anyway.