Yesterday's news that an American team has succeeded in cloning a human embryo gives added drama to a debate that will take place this week in Parliament. Emergency legislation is being put forward to ban human reproductive cloning in this country. And although the Americans deny that they'll use the new technique to clone a baby, an Italian doctor has said that he aims to do just that.

Reproductive cloning means trying to do for humans what Dr Ian Wilmut and his team did in the case of Dolly the sheep. You take a normal cell, isolate its genetic material and insert it into an egg from which the nucleus has been removed. You then get it to divide like a normal embryo and implant it into the womb of a surrogate mother. If it works, the result will be a child who - instead of being a mix of the genes of two parents - will be genetically identical to a single adult. It could be the identical twin of its father - or anyone else for that matter. It's a new twist to the phrase "designer genes".

So what's wrong? Well, the procedure is untried, untested and unsafe. In the case of the experiment that produced Dolly the sheep, 277 eggs were cloned; only 29 developed into embryos, and only one survived the birth. Cloned mice often develop genetic abnormalities after birth. And not only is cloning unsafe now. There are good scientific reasons to believe it always will be. So - don't play Russian roulette with a child's life.

But there's a deeper objection. What makes us human is that we were conceived, not engineered; born not made. Through sex, love and marriage, two people come together to create a child to whom both contribute, but which is different to both of them something new, unpredictable, a gift of otherness, not a replica of someone else. That's what gives children the space to be themselves. It's what makes being a parent being surprised by joy.

Two thousand years ago the rabbis put it well. They said: when a human being makes many coins in a single mint, they all come out the same. God makes every human being in the same image, His image, yet they all come out different. The glory of creation is that unity in heaven creates diversity down here on earth. God wants every human life to be unique, which means the right to be no one else's clone.

© Copyright Office of the Chief Rabbi 2001 - all rights reserved. Reproduction of this Web site, in whole or in part, in any form or medium without express written permission from the Office of the Chief Rabbi is prohibited.