1.   Clinton specified that only embryos already created for use through in-vitro fertilization, and later destined for disposal, could be used.

2.   Clinton specified that only embryos already created for use in in-vitro fertilization, and later destined for disposal, could be used.

3.   One logical source of embryonic cells would be the surplus embryos created through in vitro fertilization that infertile couples no longer planned to use.

4.   The cells come, not from aborted fetuses, but from surplus petri-dish embryos created in fertility programs.

5.   Those developments are more controversial and raise more moral qualms than research into surplus embryos created in fertility clinics and destined to be discarded.

6.   A single embryo creates a single cell line, which can replicate itself indefinitely.