All Folds are born with straight, unfolded ears, and those with the Fold gene will begin to show the fold usually within about 21 days.
The kittens that do not develop folded ears are known as Straights.
The original cats only had one fold in their ears, but due to selective breeding, breeders have increased the fold to a double or triple crease that causes the ear to lie totally flat against the head.

The breed's distinctive folded ears are produced by an incompletely dominant gene that affects the cartilage of the ears, causing the ears to fold forward and downward, giving a cap-like appearance to the head.
Smaller, tightly folded ears set in a cap-like fashion are preferred to a loose fold and larger ear.
The large, round eyes and rounded head, cheeks, and whisker pads add to the overall rounded appearance.
Despite the folded ears, folds still use their aural appendages to express themselves—the ears swivel to listen, lie back in anger and prick up when the treat bag rustles.
All Folds are born with straight, unfolded ears, and those with the Fold gene will begin to show the fold usually within about 21 days. The kittens that do not develop folded ears are known as Straights. The original cats only had one fold in their ears, but due to selective breeding, breeders have increased the fold to a double or triple crease that causes the ear to lie totally flat against the head.
The breed's distinctive folded ears are produced by an incompletely dominant gene that affects the cartilage of the ears, causing the ears to fold forward and downward, giving a cap-like appearance to the head. Smaller, tightly folded ears set in a cap-like fashion are preferred to a loose fold and larger ear. The large, round eyes and rounded head, cheeks, and whisker pads add to the overall rounded appearance. Despite the folded ears, folds still use their aural appendages to express themselves—the ears swivel to listen, lie back in anger and prick up when the treat bag rustles.
Scottish Fold