Board Thread:Character Discussion/@comment-26394456-20171122060155/@comment-25926288-20180108115056

Magic isn’t purely genetic; however, we also have different types of magic as well.

Adam has said that magic does require a spark as they attempted to explain why Henry couldn’t learn magic (despite being offered to in season 2).

On face value alone, the genetics appear as such:

Saviors don’t pass down their magic ability.

Powerful Dark mages pass down their magic ability.

Ice magic (which I believe is just magic with filter) appears to affect the eldest of each generation.

Still, could just be arbitrarily whatever the writers decide. It could be possible that magic lies dormant if not sparked. Rapunzel and Marcus appear normal, yet have two magical children. (I really think there are some deleted scenes because we never saw that in the flashback and Ana knew Gothel somehow.)