I looked at Mother. She was crying.
"Just tell me," I demanded. "No more guessing games."
Father sighed, put his arm around Mother, and began to talk It didn't take long to explain.
"The greatest breakthrough in the medical treatment of disease was the germ theory, but it took an astonishingly long time for doctors to realize that almost all human ailments were caused by infectious agents. A few were genetic-such as cystic fibrosis and sickle-cell anemia but those all seemed to be recessive genes that conferred a benefit when you had one of them, and killed you only if you had two. All the others--heart disease, dementia, schizophrenia, strokes, nontraumatic cerebral palsy, multiple sclerosis, most cancers, even some crimes-all were actually diseases. What disguised them from researchers for so long was the fact that these diseases were passed along in the womb, across the placenta, mostly by disease agents composed of proteins smaller than DNA. Some were passed along in the ovum. So we had no way to compare a clean, healthy organism with an infected one until we finished mapping the human genetic code and realized that these diseases weren't there. When we finally tracked them down as loose proteins in the cells, we--"
"We?" I asked.
"I speak of our forebears, of course," said Father. "Our predecessors."
"You aren't in medical research."
"Our colleagues in science," said Father. "We've come a long way to have you quibble about my choice of pronouns. And anthropology is the science of which medicine is merely a subset."
I had a snappy retort about how nobody ever asks if there's an anthropologist in the house, but I kept it to myself, mostly because I didn't want to win points here, I wanted to hear the story.
"How do you inoculate an organism against in utero infection?" asked Mother rhetorically. "How do you cleanse an ovum that has already been infected?"
"What we developed," Father began, then interrupted himself. "What was developed."
"What emerged from the development process," said Mother helpfully.
"Was," said Father, "an elegant little counterinfection. Learning from the way these protein bits worked, the researchers came up with a protein complex that hijacked the cell's DNA just the way these infectious agents did. Only, instead of destroying the host cell, our little counterinfection caused the human DNA to check aggressively inside the cell for proteins that didn't belong there. There are already mechanisms that do bits and parts of that, but this one worked damn near perfectly. Nothing was in that cell that didn't belong there. It even detected and threw out the wrong-handed proteins that caused spongiform encephalopathies."
"Now you're showing off, my love," said Mother.
"It was perfect," said Father. "And best of all, self-replicating yet nondestructive. Once you introduced it into a mother, it was in every egg in her body after a matter of days. Any child she bore would have this protection within it."
"It was perfect," said Mother. "The early tests showed that it not only prevented diseases, it cured all but the most advanced cases. It was the ultimate panacea."
"But they hadn't tested it for very long," said Father.
"There was enormous pressure," said Mother. "Not from outside, from inside the research community. When you have a cure for everything, how can you withhold it from the human race for ten years of longitudinal studies, while people die or have their lives wrecked by diseases that could be prevented with a simple inoculation?"
"It had side effects," I said, guessing the end.
"Technically, no," said Father. "It did exactly what it was supposed to do. It eradicated diseases with smaller-than-bacteria agents. Period. Nothing else. The only reason that they didn't immediately spread the counterinfection throughout the world to save as many lives as possible was because of the one foreseeable hitch. Can you think of it? It's obvious, really."
I thought. I wish I could say I came up with it quickly, but my parents were nothing if not patient. And I did come up with it after a few false tries, which I can't remember now. The correct answer: "Aging is a disease. You get this counterinfection, you don't die."
"We were concerned about a population explosion," said Mother. "Even if people completely stopped having children, we weren't sure that the existing ecosphere could sustain a population in which all the existing children grew up to be adults while none of the adults died off to make room for them. Imagine all the children entering the workforce, while the older generation, newly vigorous and extremely unlikely to die, refused to retire. It was a nightmare. So, by the mercy of God, the counterinfection was restricted to a large longitudinal study centered on Manhattan, a smallish college town in Kansas."
"There was a quarantine of sorts," said Father. "The participants accepted the rules-no physical contact with anyone outside the city during the two years of the stud: In exchange, nobody dies of any kind of disease. They jumped at it."
"The counterinfection got loose!" I said.
"No. Everybody kept to the rules. This was science, not the movies," said Father. "But in the Manhattan Project, as we inevitably called it, for the first time the test included infants, newborns, children born after the study began, children conceived after the study began. We were so interested in the result with the aging population that it had never crossed our minds that ... well, it did cure aging. The people who have it would never die of old age. The trouble was, the children were born--"
"As Neanderthals," I said, making the obvious guess.
"And over time," said Father, "as cells were replaced, the adult bodies also tried to reshape themselves. It was fatal for them. You can't take an existing body and make it into something else like that. You had a few years of perfect health, and then your bones destroyed themselves in the frantic effort to grow into new shapes. The little ones, the ones who were changed in the womb, only they survived."
"And that's who I'm seeing out there," I said.
Father nodded. "It took fifteen years to find a way to sterilize them all without our counterinfection undoing the sterilization. By then there were so many, of them that to keep them all in their natural habitat required a vast reserve. It really wasn't all that hard to get the citizens of this area to evacuate. Nobody wanted to be anywhere near Manhattan, Kansas. So once again, Homo neanderthalensis has a plot of ground here on Earth. Homo neanderthalensis, the most intelligent toolmaking species ever to evolve naturally."
"But how could the counteragent cause us to revert to an earlier stage of evolution?" I asked.
"You weren't listening," said Father.
I thought for a moment. "Homo neanderthalensis isn't an earlier stage," I said. "There was no more evolution after that."
"Only a disease," said Father.
It seemed too incredible to me, as an eleven-year-old who prided himself on understanding the world. "Human intelligence is an infection?"
"Passed from mother to child through the ovum," said Mother. "By a disease agent that alters the DNA in order to replicate itself. We should have realized it from the fact that in utero development recapitulates evolution, but there is no stage in which the fetus passes through a habiline form. We did not evolve past it. The DNA is hijacked and we are born prematurely, grossly deformed by the disease. Neotenic, erectstanding, language-mad, lacking in sense of smell, too feeble to survive on our own even as adults, in need of clothing and shelter and community to a degree that the Neanderthals never were. But ... smart."
"So now," said Father, "do you understand why medical science has to rely on inoculation to fight off cancer, so that a small percentage-far smaller than ever before in human history, but not zero-a small percentage dies? Elizio died because the only alternative we've found is for this race of perfectly healthy, immortal, dim-wilted beings to inherit the Earth."
I stood there for a long time in silence, watching the Neanderthals, trying to see how their behavior was different from ours. In the years since then, I have come to realize that there was no important difference. Being smarter hasn't made us act any differently from the Neanderthals. We make better tools. We have a longer, more thorough collective memory in the form of libraries. We can talk much more fluently about the things we do. But we still do basically the same things. We are Neanderthals, at heart.
But I did not understand this at the time. I was, after all, only eleven. I had a much more practical -- and heartless -- question.
"Why do we keep this park at all?" I asked. "I mean, they're going to live forever. And all the time they're alive, they pose a danger of this counterinfection getting loose outside the fence. Why haven't they all been killed and their bodies nuked or something so that the counteragent is eliminated?"
Mother looked appalled at my ruthlessness, but Father only patted her arm and said, "Of course he thought of that, my love."
"But so young, to be so-"
"Practical?" prompted Father. "There was a long debate over exactly this issue, and it resurfaced from time to time, though not for decades now: The ones who argued for keeping the park talked about the necessity of studying our ancestors, and some people talked about the rights of these citizens who, after all, can't help their medical condition and have committed no crime, but it was all a smoke screen. The real reason we didn't destroy them all, as you suggested, was because we didn't have the heart."
"They were our children," said Mother, crying again.
"At first," said Father. "And later, when they weren't children anymore, we still couldn't kill them. Because they had become our ancient parents."
Now, though, I have come to think that while they were both right, the answer is even deeper. We didn't kill them, and we continue not to kill them, despite the reality of all those dangers, because they are not "they" at all. There, but for the fact that we happen to be the tiniest bit ill, go we.
I had troubling dreams for months afterward. I had mood swings, alternating between aggression and despair. At times, my parents wished they had just answered my questions about Elizio by taking me to the priest and getting me on the roster of altar boys.
But they were not wrong to take me there, any more than they had been wrong not to tell me up till then. I needed to know before my education was complete. Those who do not know, who continue through adulthood oblivious, in a sense remain children, forever naive. Within the fence of the North American Wild Animal Park is the Garden of Eden, and the people there eat freely of the Tree of Life. Here, outside, in this world of thorns, we dwell in the Valley of the Shadow of Death, madly eating of the fruit of the Tree of Knowledge, as much of it as we can get before we die.
You cannot straddle the boundary. If you bring children into the world on this side of the fence, you must take them to eat the fruit of the tree not too young, not before they're able to bear it. But don't wait too long, either. Let them see, before you die, that death is truly the gift of a merciful God.