Chinese researchers say they’ve grown human cells into new ears for five children.

How it works: A scaffold, created from a mirrored, 3-D-printed replica of a patient’s healthy ear, is seeded with cartilage-creating cells taken from the person’s body. First grown in a dish, the replacement ear is then implanted beneath pre-stretched skin on the side of the patient’s head.

The results: See for yourself in the images above, from one month post-op in the top left to 30 months post-op in the bottom right. New Scientist reports that the shape, size, and angle of the ears is convincing.

But: The ears don’t really look great, and it’s unclear how they’ll change over a patient’s life. Some researchers have questioned the safety of some aspects of the procedure.

Why it matters: Using tissue engineering to grow complex shapes like this is difficult. The approach may inspire new ways to grow other complex body parts, too.