Those wanting better treatments for diseases should welcome Tuesday's announcement that medical research involving cloning human cells should be allowed. The medical applications of cloning technology could be enormous.

We are made of cells, more than there are stars in the Milky Way galaxy. Hundreds of different cell types carry out hundreds, if not thousands, of different jobs.

Yet in the beginning we were just one cell. When the sperm cell fused with the egg cell, it created the genetic blueprint of a new individual. Out of that single cell, all the other cells of our bodies emerged guided by the control of our genetic template.

Understanding that process is vital to understanding ourselves, and many scientists say that a sensible and open use of the cloning technology is crucial.

The diseases we face are diseases of our cells: when they become damaged and grow out of control the result is a cancer; when they fail to produce necessary chemicals the result can be Parkinson's disease, cystic fibrosis or muscular dystrophy; when they produce too much of a particular substance the result can be the devastation of Alzheimer's disease; when they are damaged by accident the result can be spinal paralysis. And sometimes they just get old and less efficient.

Would it not be irresponsible if scientists ignored the opportunity to gain more knowledge about the workings of the cell, so much of which has already come from cloning research? Should they not try to produce medical benefits for people who suffer? Where is the morality in not doing all one can to avoid human suffering?

But is it a slippery slope? Would research involving cloning human cells inevitably lead to cloning humans? No. In the UK a law was passed as long ago as 1990 that said, "No cloning of humans." It could not be simpler.