"Now, bear with me as I tell you about two kinds of experiments that will give hard numbers on what I'm saying. I'm not suggesting that this will answer the question. What I'm saying is it's going to give hard, factual information that will be useful. So the first one is identical twin studies done with humans that were separated at birth. I find that fascinating, principally because it says there's more to the genes than you want to imagine. And now let's do an experiment where we clone animals so that we have twins, genetically identical individuals. And let's take an animal that has interesting behavior. It's hard to argue that gorillas and/or chimpanzees don't have behaviors that are very similar to those of humans.
"So that's what I want my experiment to be—to clone gorillas or chimpanzees. And now we have behavioral tests, and I don't actually care what the tests are. In the identical twin studies, they were 'What's your favorite color?' Which is a very interesting question because it's so meaningless and stupid, and yet the fact that identical twins had an 80 percent correlation coefficient on that, even though they'd been separated at birth, I find fascinating. So let's take gorillas. What do they like to eat better, bananas or mangoes?
"So what you get as a result of that is numbers, hard numbers on the extent to which behavior is modified by a gene. Now for the more interesting experiment. We take a human embryonic stem cell, and we inject it into a monkey blastocyst [the first 130 or so cells in a newly formed embryo]. Now you know that if you take a mouse embryonic stem cell that is, say, labeled so all of the developed cells will be blue, and you inject it into a mouse blastocyst, you'll get a chimera. So it might have a blue liver and some blue muscle cells.
"Now let's do it with the human embryonic stem cell into a monkey. This is different from cloning now. We're purposely trying to make a chimera—100 chimeras. And now we're going to look through their bodies, and we're going to look to see what parts of the body the human embryonic stem cell makes. Now there'll be a monkey where the only thing that was made that is human is the big toe. That's completely uninteresting; no one will argue about that. No one will say that's an experiment you shouldn't do. And then we'll have a monkey with a human heart. Three centuries ago, if we found a monkey whose heart was human, people would have freaked out because the seat of the soul was the heart. Now no one really thinks that."
I am beginning to wonder how far he will go with an idea that is close to Frankenstein territory given today's ethics. He assures me that he has no plans to do this experiment for real.
"But the brain is different," he says. "These days, if we're forced to pick a body part where our soul is, we say it's connected to our mind, which is connected to our brain. And that comes back to this idea of what is natural. So now we have our 100 monkeys, one of them has a blue big toe, another one has a human heart. But now the interesting part of the experiment is that we can make chimeras, which have different parts of our human brains and different parts of a monkey brain.
"And one of the first-level questions we might ask is: What part of a monkey has to be human in order to have speech? I find it really intriguing, as in the movie Planet of the Apes, to walk into a lab here at Harvard and have one of the monkeys say hello to you. That makes you wonder immediately: What does this monkey think? So what you want to know first, is this just mimicry, like a parrot? And it gets back to Wittgenstein, who talked about the relationship between language and thought. So you ask me what am I excited about? That's it."
He pauses, and I tell him this would give me the heebie-jeebies: "A human brain in a monkey that is conscious; it would be a horrible freak."
"I'm not suggesting that this chimera would have the intelligence of a human."
"But how do you know it won't?"
"It's an interesting question; I find it highly unlikely that this would happen. I don't think it would. There would be just parts of the brain that were human."
"It still sounds dangerous," I say.
"What we consider to be natural is largely a function of time. Natural childbirth, natural conception, natural, natural, natural. Now let me say two things to you about this. One is, what I find people don't ask themselves about enough is: If everything is supposed to be about controlling man's intervention, why do people take antibiotics?
"Let me explain a trick, a kind of philosopher's game about natural conception. If you look at the legislation that's been proposed in most countries, they have to rule out making a genetically identical individual as a reason to ban cloning because of the existence of twins. If you didn't do this, you would be obliged to kill one of two twins. So what they're left with is that it's medically unsafe, which is absolutely true. I suggest to you that this reason is really a surrogate for a fear of doing something where they don't know the consequence, by which I mean they are afraid. Here's my puzzle. Right now, in natural childbirth, a certain percentage of all natural fertilization events end in something we call diseased or abnormal. So if you go to Massachusetts General Hospital over here, for a certain small percentage of all children, the child has a heart defect problem. So now let's look ahead: Fast-forward two generations from now, and I will contend that it will be possible, by medical advances, to make cloning [a child] by nuclear transfer safer than natural childbirth—that the cloned embryos will have a defect rate, let's call it, of less than 1 percent.
"I'm not saying this will really happen, or that it should, but let's say 20 years from now. Let's suppose the failure rate is below what you and I call the natural birthrate. Here's the puzzle: Would the government then be justified in telling the population you can no longer create children by what you and I call natural childbirth because the probability of defect is higher than it is by cloning?
"There is another point, which comes up in my discussions with the Catholic Church: There is something called natural abortion—where biology removes fertilized events by not allowing them to implant."
"You mean spontaneous abortions, or miscarriages."
"Yes. I have a hard time finding the number because books seem to give different numbers, but people have agreed on a surprisingly high number. If you take 100 fertilized eggs, let's say only 20 percent of them are going to implant and make a baby. Of the fertilization events, most of them fail. If that's true, the Catholic Church has a major problem that they fail to face up to if life begins at fertilization. Let's assume there are 10 million Catholic couples trying to have babies for their families. This would mean there are tens of thousands of fertilized eggs that do not result in the birth of a baby, and this poses a problem in terms of the Catholic Church holding funerals for all of those fertilized eggs. And when I pointed this out, they find this to be a puzzle that they don't know how to answer. One answer is that this is God's will, and that's fine, but then that gets you into this really complicated business of, is it not then God's will to have a person like me wanting to work on human embryonic stem cells?"
Later, on the phone, I ask Melton if there is any instance he can imagine that would simply cause him to halt a stem cell experiment.
"I think it's uninteresting to live in a society where one is so afraid of the unknown that you won't try new things. I'll think about the dangers, because I haven't thought about them enough. I should think about why one shouldn't do that experiment."
Adapted from The Geneticist Who Played Hoops With My DNA...And Other Masterminds from the Frontiers of Biotech
by David Ewing Duncan, to be published in May 2005 by William Morrow. Copyright 2005 by David Ewing Duncan. All Rights Reserved.