One of the biggest hurdles to human embryonic stem cell research is the fact that embryos need to be destroyed in the process. But researchers at Advanced Cell Technology reported some success in extracting stem cells from excess invitro fertilization (IVF) embryos while leaving the embryo intact and, therefore, theoretically able to continue normal development as a fetus. It's similar to the pre-implantation genetic diagnosis procedure used in IVF clinics to select out embryos free of genetic abnormalities.