Scientists at a technology company said Sunday they have created human embryos through cloning, drawing criticism from President Bush and lawmakers and raising new ethical questions. Advanced Cell ...

Learn about our Editorial Policies. It is allowing people to do biochemistry with mammalian embryos that they couldn’t do otherwise. After a sperm fertilizes an egg, the totipotent cell divides into a ...

Now - the clever bit. The cells on the inside layer of this very early embryo can make all of the cell types needed in your body. They're called stem cells. The stem cells continue to divide by ...