Following in vitro fertilization procedures, families have traditionally had three options for unused embryos that were fertilized but never implanted into a woman's womb. They could give them to sterile couples, donate them to research facilities or discard them.
StemLifeLine, a California-based biotechnology company, is now offering a controversial but potentially life-saving fourth option.
StemLifeLine allows families to "develop" remaining embryos into "personalized stem cell lines," the first theoretical step in creating cures for a host of debilitating and deadly diseases.
"The embryonic stem cells could be used to develop cures for diseases like diabetes, lymphoma and Parkinson's," said Dr. Russell Foulk, director of two of the four fertility clinics putting patients in touch with StemLifeLine and a member of the company's board of directors.
StemLifeLine is betting that the promise of stem cells will encourage people to buy its services. However, since so much of that potential remains unknown, some medical ethicists worry the company is selling empty promises.
"It's a gimmick and many of the claims rest on hot air," said Arthur Caplan, professor of bioethics at the University of Pennsylvania.
Caplan said StemLifeLine was "offering a unique product" but questioned the ethics of selling people stem cell lines as if they were a guaranteed cure.
"In fact any clinic can do it, just like any clinic can freeze embryos. The problem is no one has made anything useful out of stem cells," he said.
The promise of stem cells lies in their ability to grow into specialized cells like those found in the brain or bone marrow. Stem cell lines are those cells that have been removed from fertilized embryos and have the potential to become differentiated cells.
StemLifeLine is offering what they call "personalized stem cell lines." Those lines could then be turned into treatments that could be specially designed genetic matches just for donors, Foulk said.
"The advantage of using genetically similar material is the decreased chance of rejection. We can already take adult stem cells from bone marrow to help treat leukemia but they have to come from relatives," he said
Caplan is not sure this rationale holds water either.
"It is still unclear if it matters where the embryos come from. Part of the promise of stem cells is that they can be taken from any embryo."
The federal government prohibits laboratories from receiving federal funds to do the same sort of science StemLifeLine is doing.
President Bush has twice vetoed legislation that would expand funding for stem cell research. Critics of the president contend that his administration would prefer leftover embryos from fertility treatments were thrown away rather than used in research.
StemLifeLine is keen to point out that only remaining embryos would be used to create stem cell lines and no embryos would be created solely for the purpose of making lines.