OOC: I am not sure why the pony version of the Kinsey scale is named after King “Kingsley” Sombra, but the pun was too good to resist…

Wouldn't Rarity's behavior imply a degree of speciesism? Ferucentrism or something?

OOC: Official ruling, while “speciesism” would technically be the more accurate term, it sounds clunky and awkward. People are much more familiar with racism and the concepts are similar enough that people will understand what I mean, so let’s just call it racism. 

Rarity, these species are mules, zebras, donkeys and other species are cousins ​​species of ponies, because all species are genealogical tree of ponies, do not you know? then it is your fault because you made a racist against all species, bitch.
Anonymous

OOC: Countering racism with sexism… uh oh, you’re crossing the streams! 

OOC: For an example of similar ideas being discussed and refuted in human history, consult this.

OOC: This isn’t like with incest where there’s a number of recessive diseases that can cause problems. Quite the opposite, in the case of mules, hybridizing is quite advantageous.

I’m pretty sure most parents care more about raising a healthy child that will grow into a responsible and emotionally fulfilled adult than they care about making a sperm/egg bank for the future…