You are completely wrong about this. This experiment never use any genetic engineering or human cells for that matter. A scafolding of biodegradeable material made out of the same material dissolving stitches are made out of was fashioned into the shape of a 3 year old's ear. Carilage from a cow was then placed in the scafolding and the whole thing was implanted under the skin, but above the muscle of a nude mouse.

A nude mouse was used because they have no immune system that would reject the cow cells. The mouse started to grow very thin blood vessels that were able to supply the cartilage with nutrients and the cartilage started to grow with the mouse. By the time the scafolding material dissolved, there was enough cartilage there to maintain the structure of the outer ear.

It was never transplanted because, since it contained no human tissue, it would have been rejected by a human.

Not genetic engineering, just good old science.

Holy. Flippin. Muffincakes. That's just disturbing....

Thanks the author!