The statement concludes that certain experiments will require researchers to create new embryos specifically for research, a practice that is controversial and prohibited in some countries. (sciencemag.org)
In theory, new embryos then could be created by combining converted egg or sperm cells with natural ones, or by combining eggs with sperm cells derived from different donor animals. (discovermagazine.com)
Some can reproduce from outgrowths of stems, roots, and bulbs, but others are even more radical, able to create new embryos from single somatic cells. (science.sciencemag.org)