There is a French folk tale of a family in which one of the sons is only half a man. (It's not impossible for a child to be born that way.) The young man gets on the good side of the fairies, and attains magical powers, so he can change himself into various things, make his parents rich, and make the local princess pregnant without having sex with her. (So, of course, she has to marry him.)

A Breton story tells of Ugly Jan, who is also remarkably unintelligent, but can, by saying "By the grace of God, may such and such happen." Make anything happen. But he's so dumb he never uses his power until a load of wood gets too heavy, then he says, "By the grace of God, may the load of wood carry me." When the local princess sees him going by being carried by a load of wood and laughs he says, "By the Grace of God, may the princess get pregnant." They also wind up married. When she finds out about his gift, the princess suggests Jan wish himself intelligent and handsome, so he does.

There's a Japanese version of the hunchbak and the fairies, that involves the Japanese ogres, called Oni, and two old men with cysts on their cheeks.