DR SIMON JONES' letter (Chronicle, May 8) contained little to illuminate me. He was wrong about me and right about little else. I found little trace of the dispassionate scientific inquiry that he sought to defend.

I am a graduate chemist who would have gone on to a master's degree in molecular biology if bad health had not intervened (not quite the scientific illiterate that Dr Jones assumes I am). I am a Christian but few would describe me as a fundamentalist.

I await some explanation as to how human DNA developing for up to 14 days in the egg cell of a cow will throw light on Alzheimer's disease or its cure, far less cancer. Perhaps Dr Jones could enlighten us about this rather than just indulge in name calling.

In the absence of this, I will attempt to do the job for him. The philosopher's stones of modern molecular biology are stem cells. Just like the alchemists' philosopher's stone was supposed to be able to turn anything into gold, a stem cell is capable of growing into any cell in a mature human body. Stem cells exist in the early embryo and later differentiate to form every sort of cell. Stem cells could be used to replace the damaged cells in the pancreas that lead to diabetes, those in the brain in Alzheimer's and Parkinson's disease.

This all seems very attractive. Unfortunately, cells are hard to obtain in sufficient numbers. Current sources include cord blood from newborn babies and the bodies of aborted babies. The first of these is in short supply and the second is under attack on moral grounds. I stand open to correction but it is my understanding that the hybrid embryo experiments are aimed at producing stem cells in a slightly less morally repugnant way. The trouble is that I am not convinced that this is more acceptable.

I wish I could share Dr Jones' very optimistic view of science as a major humanising influence. When I see a patient in an ITU with tubes and wires attached and machines ventilating his lungs and causing his heart to beat, I am not convinced that science has humanised him. He has surrendered all his human dignity to the new religion of trying to live forever (let me end my days in a hospice; not an ITU). Does research without borders lead to more humanity? (it certainly didn't in Hitler's hideous concentration camp experiments)

I believe that we need to tread a careful path that benefits from scientific research without dehumanising us in the process. The present proposal is to legalise things that almost every other civilised country has banned.

JOHN C MURPHY Camrose Avenue, Feltham.