Letter: When life begins

Sir: I wholeheartedly applaud Andrew Brown's call for rational principles to be used in deciding such difficult ethical issues as cloning ("The future should not be hostage to the yuck factor", 25 June). If only he hadn't followed it up with a piece of illogic. He argues that it is "ridiculous" to call a human embryo a "human being" because not only can "we do things an embryo can't" but also because we have grown out of capabilities which, as an embryo, we had.

I can think of numerous abilities that I have gained since age (say) 10 and more than a few abilities I had then which I have since lost. In future I will doubtless lose more abilities still. At what point will I have lost enough capabilities to be counted human?

I have an open mind on embryo research, but the inescapable (albeit inconvenient) fact is that an embryo is indeed a human being - if only because it has the key ability to grow into a fully-functioning foetus, and then a baby, a child, an adolescent and finally an adult human - all of them with the same identifiable human DNA. In other words, it is human, alive and an individual.

J CHARLES HARRIS

London NW3