Couples who have had children via in vitro fertilization are often left with extra embryos–and the rather difficult decision of what to do with them. Embryos can be donated to research or to other couples, destroyed, or left languishing in frozen storage. But now a California-based biotech startup is offering a new option: to use these embryos to create personalized stem-cell lines for couples or their families.

The company, StemLifeLine, describes its service as “buying insurance for the future.” From its website:

We believe that in the not so distant future, our clients will achieve profound therapeutic benefits from personalized therapies created from their personal stem cell lines.

The company’s website does not divulge how much the process costs.

The downside: While scientists have shown that embryonic stem cells can be converted into many types of cells, including brain and heart cells, no current FDA-approved therapy exists that uses embryonic stem cells. Extensive animal research is taking place, and clinical trials are on the horizon. But it’s not yet clear how effective–or practical–such treatments will be. Indeed, some ethicists think the company is selling false hope. From an ABC news story:

“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.