Glossary
Blastocyst
An embryo The early developmental stage of a multicellular organism, typically occurring after fertilization of an egg cell by a sperm cell. embryo The early developmental stage of a multicellular organism, typically occurring after fertilization of an egg cell by a sperm cell. in its very early stage, usually 5 to 6 days old, that has not implanted or attached to a uterus. It is made up of a small group of inner cells, which will develop into the embryo, and an outer layer of cells, which will develop into the placenta and amniotic membranes.
All of the embryonic stem cell lines used in research are created from five to six-day-old blastocysts — most commonly referred to as embryos — that are left over from in vitro A process, procedure or study performed in a test tube or lab dish rather than in a living organism. in vitro A process, procedure or study performed in a test tube or lab dish rather than in a living organism. fertilization, or IVF, procedures. Each cycle of IVF produces many blastocysts, some of which are implanted into a uterus to in the hopes an individual or couple will become pregnant. After a successful implantation, people with left over blastocysts must decide what to do with them. They may continue to pay to store the embryos in their IVF clinic’s freezer, defrost and discard the embryos, or choose to donate them for research.