Settled Science that Is 'Controversial'

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Embryonic Stem Cell Research Is Necessary

Embryonic stem cells are "pluripotent"; that is, they have the ability to differentiate into any type of cell in the body. Biomedical scientists believe studying them is vital for regenerative medicine.

Some people object to embryonic stem cell research on ethical grounds because harvesting them usually causes the death of the embryo. (Although, scientists have shown it may be possible to extract the cells without killing the embryo, similar to the process used for preimplantation genetic screening of embryos created by in vitro fertilization.) Those who object to embryonic stem cells often point to adult stem cells and induced pluripotent stem cells as superior alternatives. But this isn't necessarily true.

Unlike embryonic stem cells, adult stem cells are merely "multipotent"; that is, they are dedicated to a particular lineage and can only differentiate into certain types of cells. For example, bone marrow contains two types of adult stem cells, hematopoietic stem cells (which differentiate into blood and immune cells) and mesenchymal stem cells (which differentiate into bone, cartilage and fat cells). Both embryonic and adult stem cells can serve useful purposes, but embryonic stem cells are far more versatile.

Induced pluripotent stem cells are created from cells which have been reverted to a pluripotent (embryonic-like) state by genetic manipulation. These cells show tremendous potential, but it is currently unclear if they are as versatile as actual embryonic stem cells. Indeed, many differences have been noted between the two types of cells.

As a result, biomedical scientists support research with all three cell types.

(Image: Public domain/Wikimedia Commons)

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