Fimbulfamb

You could, one way or the other, remove electrons from metals. But soon you'd see the metal fall apart, since the binding electrons are those you'd be shooting away. This would also be an inefficient way of 'extracting' energy, since the kinetic energy imposed on the electrons would originate in the field you used to extract them. It would get progressively harder to get the negatively charged electrons to leave the increasingly positively charged metal. Also, I can't see how a magnetic field would be useful, since it, to my knowledge, only propels already moving charges in circles. The field of an incredibly large positive charge might be suited for the purpose. All of this is not at all practical, and not even close to useful, unfortunately.

I disagree with those here that contend that religions are the sole barrier. There are social issues as well. Imagine, if you will, a society where a lot of embryonic stem cells would need to be harvested from live embryos to provide treatments for various diseases. Compensations would be made to donors; now, this could lead to an influx of poor women, looking desperately for the money. (Abortion is not a pleasant process.) This problem will probably be sidestepped, though, as pluripotent stem cells are being generated 'from scratch'. It's worth noting, though, that although religious fundamentalists have clouded the scene with irrational arguments against stem cell research, there are real issues they're alienating in the process.

If such a field is produced (which it very probably is, since there definitely are charges moving about in the body) it will be very weak, since each charge's field points in a random direction, so as to cancel out with others.

Here you can see the process of a chemical reaction. (Try to ignore all the letters and arrows and concentrate on the black path.) The graph shows energy levels as a function of time. Read from left to right you'll notice that to start the reaction a lot of energy is needed, and some of that energy is then contained in the resulting product. This is equivalent to the production of ATP. When ATP->ADP this happens backwards. Some energy is needed to get over the 'energy barrier', known as the activation energy, of the reaction, after which a considerable amount of energy is released (more than was needed to activate the reaction). Thus energy is needed, but also released, in the process of ATP->ADP.