1. They currently only allow infertile women to be treated in a clinic to carry an embryo made from a donated egg and sperm.
2. They're present in an embryo only days after conception and are ethically sensitive because culling stem cells destroys the embryo.
3. Teeth may not be visible until long after birth, but they start to form early in embryo development.
4. The central obstacle is that during the development of a cloned embryo the genetic material which is parcelled up as a cell splits in two.
5. The Savages have said the fertility clinic transferred the wrong frozen embryo to Carolyn's womb in early February.
6. The embryo in the womb of a rich mother enjoys better nutrition than that in a poor mother.
7. Researchers created a fertilised embryo from the couple's egg and sperm in a laboratory and then implanted in Lesley Brown's womb.
8. in embryo
8. A human embryo is pictured in the eighth week of pregnancy in this undated photo by Swedish photographer Lennart Nilsson.
9. Wednesday at the Tianjin veterinary research institute, a research body that has been engaged in the embryo cloning project since 2002.
10. Surgeons said the tumor was the embryo of an undeveloped twin sister lodged in Zheng's stomach.