Frequently Asked Questions (FAQs) about stem cells

What are stem cells?

A cell that has the ability to continuously divide and differentiate (develop) into various other kind(s) of cells/tissues. Some of these cells are "immortal" have the ability to be grown in the laboratory indefinitely.

What kinds of stem cells are there?

Three different categories of stem cells exist. Totipotent stem cells can produce an entire human being, so are only useful in producing babies. Pluripotent stem cells are isolated by destroying early human embryos and culturing the cells under laboratory conditions. These are the cells that are proposed to be studied by this initiative. Adult stem cells are isolated from adult tissues, cord blood, etc. and have been used extensively in studies involving stem cell therapies. No human embryos are destroyed in theses therapies. Studies using these cells will not be funded by this initiative - even if they prove to be more useful for cell-based medical therapies.

Stem cell type Description Examples
Totipotent Each cell can develop into a new individual Cells from early (1-3 days) embryos
Pluripotent Cells can form any (over 200) cell types Some cells of blastocyst (5 to 14 days)
Multipotent Cells differentiated, but can form a number of other tissues Fetal tissue, cord blood, and adult stem cells

Aren't embryonic stem cells better for therapy?

Supporters of Proposition 71 would like you to believe that embryonic stem cells will be the magic bullet to cure all kinds of diseases. However, the facts show that adults stem cells are currently used in the treatment of 45 different diseases. Embryonic stem cells have never been used to treat any human diseases, despite being available since 1998. Please see Won't Prop 71 funded research provide cures for a host of diseases? for more information.

Aren't embryonic stem cells more versatile than adult stem cells?

Originally, scientists believed that only embryonic stem cells could develop into all of the 220+ different kinds of cells found in the human body. However, a recent study shows that blood from umbilical cords of newborns contains cells that can form any kind of cell. See our news page for more information.

Doesn't this proposition prohibit human cloning?

Proposition 71 gives scientists a constitutional right to clone human embryos. Proposition 71 bans reproductive cloning, although this is already banned by California law. However, the technology that drives "therapeutic" cloning is identical to that required to enable reproductive cloning. All that is necessary to produce a human clone is to implant the cloned embryos into a womb. Therefore cloning of human beings will be facilitated if Proposition 71 passes.