In January 2001, scientists at Advanced Cell Technologies, Massachsetts, USA announced that they had for the first time successfully grown kidneys using cloning technology. The technique took a DNA-containing nucleus from a single cow skin cell and fused it with a host egg. The egg multiplied into an embryo rich in stem cells. These cells were chemically manipulated to grow into kidney cells, using an artifical kidney-shaped scaffold. Several of these miniature kidneys were grown in this way and transplanted back into the cow, where they began to produce urine. Each of the kidneys were several cm (a few inches) long.