She Has Her Mother's Laugh

PROLOGUE The worst scares of my life have usually come in unfamiliar places. I still panic a bit when I remember traveling into a Sumatran jungle only to discover my brother, Ben, had dengue fever. I lose a bit of breath any time I think about a night in Bujumbura when a friend and I got mugged. My fingers still curl when I recall a fossil-mad paleontologist leading me to the slick mossy edge of a Newfoundland cliff in search of Precambrian life. But the greatest scare of all, the one that made the world suddenly unfamiliar, swept over me while I was sitting with my wife, Grace, in the comfort of an obstetrician's office. Grace was pregnant with our first child, and our obstetrician had insisted we meet with a genetics counselor. We didn't see the point. We felt untroubled in being carried along into the future, wherever we might end up. We knew Grace had a second heartbeat inside her, a healthy one, and that seemed enough to know. We didn't even want to find out if the baby was a girl or a boy. We would just debate names in two columns: Liam or Henry, Charlotte or Catherine. Still, our doctor insisted. And so one afternoon we went to an office in lower Manhattan, where we sat down with a middle-aged woman, perhaps a decade older than us. She was cheerful and clear, talking about our child's health beyond what the thrum of a heartbeat could tell us. We were politely cool, wanting to end this appointment as soon as possible. We had already talked about the risks we faced starting a family in our thirties, the climbing odds that our children might have Down syndrome. We agreed that we'd deal with whatever challenges our child faced. I felt proud of my commitment. But now, when I look back at my younger self, I'm not so impressed. I didn't know anything at the time about what it's actually like raising a child with Down syndrome. A few years later, I would get to know some parents who were doing just that. Through them, I would get a glimpse of that life: of round after round of heart surgeries, of the struggle to teach children how to behave with outsiders, of the worries about a child's future after one's own death. But as we sat that day with our genetics counselor, I was still blithe, still confident. The counselor could tell we didn't want to be there, but she managed to keep the conversation alive. Down syndrome was not the only thing expectant parents should think about, she said. It was possible that the two of us carried genetic variations that we could pass down to our child, causing other disorders. The counselor took out a piece of paper and drew a family tree, to show us how genes were inherited. "You don't have to explain all that to us," I assured her. After all, I wrote about things like genes for a living. I didn't need a high school lecture. "Well, let me ask you a little about your family," she replied. It was 2001. A few months beforehand, two geneticists had come to the White House to stand next to President Bill Clinton for an announcement. "We are here to celebrate the completion of the first survey of the entire human genome," Clinton said. "Without a doubt, this is the most important, most wondrous map ever produced by humankind." The "entire human genome" that Clinton was hailing didn't come from any single person on Earth. It was an error-ridden draft, a collage of genetic material pieced together from a mix of people. And it had cost $3 billion. Rough as it was, however, its completion was a milestone in the history of science. A rough map is far better than no map at all. Scientists began to compare the human genome to the genomes of other species, in order to learn on a molecular level how we evolved from common ancestors. They could examine the twenty thousand-odd genes that encode human proteins, one at a time, to learn about how they helped make a human and how they helped make us sick. In 2001, Grace and I couldn't ex