From the start, embryonic stem cells (ESCs) have been at the center of a scientific and ethical debate. For that reason, many people vested hope in adult stem cells.

We now know, though, that this hope was largely misplaced.

It had been thought that adult stem cells can do everything that ESCs do… but without the moral complexities.

Biologically, this isn’t true. Embryonic cells have complete regenerative ability. They can also engraft, which means they can integrate themselves into other tissues.

Adult stem cells release compounds that aid healing, but they don’t engraft. They also age and over time must be replaced with new adult stem cell lines.

This does not just raise issues of cost and safety. Most people don’t know that embryonic stem cells become “adult stem cells” about eight weeks after conception. This is when the embryo quite suddenly becomes a fetus.

It seems that some stem cell companies that tout their use of adult stem cells actually use cell lines derived from aborted fetuses.

ESCs are derived from unused fertilized ovum created to treat infertility using in vitro fertilization (IVF). These cells are routinely discarded following IVF, which is a common procedure.

According to sources cited in Forbes, there are about 350,000 IVF babies born each year. There are likely more than 900,000 people who were IVF babies now alive in the United States.

Embryonic or pluripotent stem cells are biologically immortal. This means they can replicate under the right conditions essentially forever.

So the handful of ESC lines approved for government funding under President George Bush and Barack Obama will never have to be replenished. In theory, they could form the basis of treatments for an infinite number of patients… forever.

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