Pros and Cons of Embryonic and Adult Stem Cells
Cell Comparisons: Embryonic vs. Adult

There are significant medical and scientific differences between embryonic and adult stem cell research and therapy. Here is a comparison between the two types, including some of the advantages and disadvantages of each.

Embryonic Stem Cell Advantages
1. Flexible—appear to have the potential to make any cell
2. Immortal—one ES cell line can potentially provide an endless supply of cells with
    defined characteristics
3. Availability—embryos from in vitro fertilization clinics

Embryonic Stem Cell Disadvantages
1. Difficult to differentiate uniformly and homogeneously into a target tissue
2. Immunogenic—ES cells from a random embryo donor are likely to be rejected
    after transplantation
3. Tumorigenic—Capable of forming tumors or promoting tumor formation
4. Destruction of developing human life

Adult Stem Cell Advantages
1. Special adult-type stem cells from bone marrow and from umbilical cord have been
    isolated recently which appear to be as flexible as the embryonic type
2. Already somewhat specialized—inducement may be simpler
3. Not immunogenic—recipients who receive the products of their own stem cells will
    not experience immune rejection
4. Relative ease of procurement—some adult stem cells are easy to harvest (skin,
    muscle, marrow, fat), while others may be more difficult to obtain (brain stem cells).
    Umbilical and placental stem cells are likely to be readily available
5. Non-tumorigenic—tend not to form tumors
6. No harm done to the donor

Adult Stem Cell Disadvantages
1. Limited quantity—can sometimes be difficult to obtain in large numbers
2. Finite—may not live as long as ES cells in culture
3. Less flexible (with the exception of #1 above)—may be more difficult to reprogram to
    form other tissue types