Related by context. Frequent words. (Click for all words.) 66 embryos 63 embryo 63 oocytes 61 cloned embryos 59 Embryos 57 germ cells 56 stem cells 55 fertilized eggs 55 embryonic cells 53 fertilized egg 52 human embryos 52 induced pluripotent stem cells 52 ovarian tissue 52 ovary 52 neural stem cells 51 ES cells 50 somatic cell nuclear 50 embryonic stem cells 50 frozen embryos 50 ovaries 50 fetuses 50 embryonic 49 cells 49 follicles 49 Adult stem cells 49 pluripotent stem cells 48 islet cells 48 Embryonic stem cells 48 progenitor cells 48 bone marrow stem cells 48 pluripotent 47 adult stem cells 47 Stem cells 47 iPS cells 47 destroying embryos 47 therapeutic cloning 47 vitro fertilization 46 placentas 46 stem cell 45 chromosomal abnormalities 45 sperm 45 testes 45 tumors 45 ova 45 fertilized 44 Cells 44 genetic abnormalities 44 PGD 44 transgenic mice 44 vitro fertilization IVF 43 lung tumors 43 amniotic fluid 43 mesenchymal stem cells 43 vitro 43 testis 43 parthenogenesis 43 progenitors 43 IVF 43 eggs 43 ovarian 43 fertility treatments 43 fertility clinics 43 fetus 42 thymus 42 genetically identical 42 Embryo 42 cloned 42 tissue 41 malignant tumors 41 malignant cells 41 fibroblasts 41 tumor cells 41 autologous 41 reproductive cloning 41 breast tumors 41 umbilical cords 41 melanocytes 41 stem cells derived 41 prostate tumors 41 mutant mice 41 fertilization 41 diseased tissue 40 transgenic 40 mammalian cells 40 mice 40 ovaries removed 40 implantation 40 cysts 40 cloning 40 assisted reproduction 40 recombinant DNA 40 assisted reproductive 40 wombs 40 neurons 40 lymphocytes 40 tadpoles 40 knockout mice 40 umbilical cord blood 40 islets 40 clones 40 tissues