I've got to admit that when I first started watching the show, I thought Dash was a stallion but since she looks like a mare with her eyelashes and muzzle, it obviously proves that she is one but you my friend, made me lean more to the stallion side. But then again Rainbow does have a few girly parts of her personality, not just being all cool and athletic. You know like her fangirl scream? It'll be pretty awkward for a male to act like that.