What are Stem cells and why are they so controversial?

Question:I've looked it up on Wikipedia but I still have no idea what they are exactly and why there is so much debate on them at the moment? Is it somthing to do with cloning, If you have comments on cloning, please share them,
Thanks!

Best Answer - Chosen by Asker: I've looked it up on Wikipedia but I still have no idea what they are exactly and why there is so much debate on them at the moment? Is it somthing to do with cloning, If you have comments on cloning, please share them,
Thanks!

The only controversy is the source of the stem cells. Stem cells are pre-specialized human cells. Every sell of your body contains the same DNA sequence, yet some are bone, soime are nerves, some are skin, some organs - and they look nothing like one another even though all have the same DNA. Stem cells are basic cells that have not specialized into a specific tissue of the body. Becasue they have not, they can in theory be placed anywhere in the body and as they grow and reproduce they will become like the adjacent cells, replacing or restoring function to damaged areas. Stem cells have the ability to become any other kind of cell and have the potential to cure all kinds of diseases - but currently have proven effects in only a very few instances. Things do look promising.

So the controversy is in where to get stem cells. Human embryos start out as a clump of stem cells. There are many human embyos sitting frozen in fertitlity labs that will never be used to create a pregnancy. Some scientists want to harvest the cells in these embryos - which will destroy the embryo. others believe that is destroying a human life and there you have the controversy.

Another potential source is cloning. Scientist would rather use stem cells from the person to treat that person instead of stem cells from a foreign embryo, which may be rejected as foreign invaders. But humans don't have a ready supply of embryonic stem cells within their bodies. But in theory you could clone the person into an embryo, and then harvest the stem cells. Now there are two controversies - you have cloned a human being (which has not yet been done) and destroyed an embryo - a human life to some people.

All of this may be moot. The latest research is the engineering of embyoinic-like stem cells from the patient's own skin cells. If this holds up, then there is a way of creating stem cells from the patients own body without cloning and without destroying an embryo. End of controversy.

Stem cells are the master cells of the human body. They can divide to produce copies of themselves and many other types of cell. They are found in various parts of the human body at every stage of development from embryo to adult. Stem cells taken from embryos that are just a few days old, can turn into any of the 300 different types of cell that make up the adult body.

Why are stem cells useful?
Because stem cells are so versatile, they could potentially be used to repair and replace damaged human tissue. In future it is hoped that stem cells could be used to treat and cure a variety of diseases and injuries including Parkinson's disease, stroke and diabetes.

Where do the embryos come from?
Embryonic stem cells can be taken from spare human embryos left over from fertility treatments, or from cloned human embryos developed in the laboratory. This can only occur if fully informed consent has been obtained from the donors. One method for making cloned embryos is called nuclear transfer. During this process, genetic material or DNA from a donor is inserted into an empty egg cell. After the resulting hybrid cell has been 'activated' (normally using an electrical pulse), it begins to divide, creating new cells and forming a cloned embryo.

Stem cells themselves are cells at a primitive stage of development that can turn into fat, bone, muscle, or nerve cells. They are found in umbilical cord blood. By themselves there's nothing wrong with them. The controversy comes from the desire to harvest them from embryos (this kills the embryos, which prevents the development of whatever animal the embryo could have turned into). Stem cells seem like they would be incredibly useful for a whole slue of diseases, including Parkinson's, diabetes, MS, spinal cord paralysis, and so on.

Stem cells are basically "seamonkeys" that build babies out of molecules. DNA is like their blueprint. Using stem cells is controversial, because it is essentially like slavery. We are taking the stem cells into captivity and forcing them to rebuild our bodies, instead of building babies, their true calling.

The controversy is about human life being destroyed for the furtherment of health. Bush signed into law that no federal funding will go to research involving human embryo destruction to produce more stem cells. The same types of stem cells can be found in human umbilical cords and is being used instead.

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If you think about it, each cell in your body has all the DNA necessary to be any kind of cell. Liver cells have the DNA to produce stuff that is only supposed to be found in the brain, your brain cells have the DNA needed to produce food-digesting enzymes, and so on and so on. Can you imagine the chaos that would ensue if all these cells actually MADE all that stuff?!

Instead, most of those sections of DNA are 'turned off' by various means. Often it's by attaching something to parts of the DNA so it can't be used by a cell. As you can imagine from the implications above, most genes in most adult cells are, in fact, completely inaccessible.

Some of the cells in your body have less of that DNA blocked off. In some cases, this is because when the cells divide they turn into lots of different things. Cells in your bone marrow, for example, turn into more marrow, white blood cells, and red blood cells. These kinds of cells are called stem cells.

If a doctor could control what new cells were going to turn into from the outside, he might get a clump of cells to become a heart, grow new skin, or turn into things too small for us to ever be able to transplant. This has already been done to an extent. If the promise of the field is fulfilled, it would mean that almost any injury to your body could be repaired as good as new. A very, VERY good thing.

The problem is that unless scientists find a way to remove those DNA blocks, the only stem cells that can become ANYTHING are in embryoes too young to have any tissues at all. And you have to take an embryo apart to get those stem cells. To some people, this is no different from killing a baby. Controversial to say the least!

There are already some good answers here, but I want to take a second and tell you that not ALL stem cells come from embryos. Scientists are actually finding new sources for stem cells all the time.

Currently the most promising one is umbilical cord blood. Want to know what some doctors in Minnesota did with umbilical cord blood that was 6 years old? They saved my daughter's life. See 'source' below.