Why Human Cloning Shouldn't be a Big Worry

Identical twins are more similar to one another than a clone
will be to the person cloned.President Obama lifted the ban on federal funding of embryonic stem cell research last Monday. Many researchers breathed a sigh of relief as they could finally get to work using these cells to find treatments and even cures for many debilitating diseases and injuries.

Of course, these cells aren't any less controversial than they were eight years ago. Researchers will still need to destroy embryos to get these cells (at least until they perfect iPS cells which would make this part of the debate moot). Anyone who considers an embryo made up of a few hundred cells to be alive will protest that embryo's destruction.

This is a legitimate argument based on when someone believes life begins. But some protests I heard were from people worried about embryonic stem cells being used to clone humans. What I can't figure out is why anyone would want to clone someone.

Cloning won't be like it is in the movies. Scientists won't take a cell from someone and make an exact copy of a person who is the same age and has the same memory.

Instead, a human will be cloned like any other mammal. First they'll remove the DNA-containing nucleus from an egg. Then they'll fuse that egg with a cell from the person they want to clone.

This "fertilized egg" will then have to grow and develop in a surrogate mother, be born, and then have to grow up. The clone won't have any of the original's memories.

In essence, a clone would be more like an identical twin who has been reared apart from his or her twin. Even though identical twins reared apart have a lot of similarities, they have a lot of differences, too. One article I saw put the amount of behavior/personality similarity due to genes at something around 50%.

And a clone will probably be more different than that. When the cell's nucleus is put into the egg, scientists erase a lot of the markings on the DNA that originally turned it into an adult cell. This "fertilized egg" is now a blank cell which can be shaped by both its genes AND its environment.

Identical twins develop in the same womb at the same time and so are exposed to the same sorts of environmental effects. A clone would not be. And these environmental factors can affect how we develop. They can even alter DNA and as a result, alter who we become.

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