[@DocentHorsecock](/images/82208#comment_172397)
Ironically, G5 canonically has the cutiemarks only on one side. The actual reason for this is probably to match the toys which are kept as cheap as possible (even most G4 toys only had one mark IIRC).
However I fanon that this was one of many lingering traces of magic, but their was only enough left to do one side. After magic has been around long enough, cutiesynthesis will once again produce two, and maybe later those who already had one will get the other. Other examples of trace magic include:
1.) Short-range telekinesis on the hooves to allow manipulation
2.) Hitch's attracting his "squad" (two seagulls and a crab)
3.) Izzy's ability to see "sparkle" around Ponies and the penetrating power of her horn allowing her to literally "spill the beans" and later "woodpecker" down a tree.
Ironically, G5 canonically has the cutiemarks only on one side. The actual reason for this is probably to match the toys which are kept as cheap as possible (even most G4 toys only had one mark IIRC).
However I fanon that this was one of many lingering traces of magic, but their was only enough left to do one side. After magic has been around long enough, cutiesynthesis will once again produce two, and maybe later those who already had one will get the other. Other examples of trace magic include:
1.) Short-range telekinesis on the hooves to allow manipulation
2.) Hitch's attracting his "squad" (two seagulls and a crab)
3.) Izzy's ability to see "sparkle" around Ponies and the penetrating power of her horn allowing her to literally "spill the beans" and later "woodpecker" down a tree.