Yes, logically all we know is that Emma is special because she is the Savior, not the rules for people born of true love or even if magic is hereditary. Charming is told by his mother she had true love and neither twin showed magic. So you cannot even explain away Ella by saying her baby was was born in pre-magic SB. Nor can you draw any conclusion about Henry.
Neither Snow nor Charming are shown as magical, except for the animal thing Snow has. So we cannot say whether Henry is.
“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn't. And contrary wise, what is, it wouldn't be. And what it wouldn't be, it would. You see?” -- Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass