“No.”

“Everyone with Huntington’s knows her name. She’s the president of the Hereditary Disease Foundation, which spearheaded the search for the Huntington’s gene. Like Arlo, she’s got a fifty-fifty chance of having Huntington’s — her mother died of the disease — and she’s never taken the test, either.”

“I don’t understand why people don’t take it. I’d want to know.”

Pierre sighed, thinking again of what Shari had said to him. “That’s what everyone who isn’t at risk says. But it’s not that simple. If you find out you’ve got the disease, you lose all hope. It’s inescapable. At least now, I have some hope…”

Molly nodded slightly.

“And — and, well, I sometimes have trouble getting through the night, Molly. I’ve… contemplated suicide. Lots of Huntington’s at-risks have. I’ve… come close a couple of times. What’s kept me from doing it is the chance that maybe I don’t have the disease.” He sighed, trying to decide what to say next. “One study showed that twenty-five percent of those who do take the test and are found to have the defective gene actually attempt suicide — and one in four of those succeeds. I’m… I’m not sure I could make it through all the dark nights if I knew for sure I had it.”

“But the flip side is that if you found you didn’t have it, you could relax.”

“Flip side is almost exactly right. It is a flip of the coin; the chances are exactly fifty-fifty. But I’m afraid you’re wrong when you say I could relax.

Fully ten percent of those who take the test and find they don’t have the disease still end up with severe emotional problems.”

“Why on earth would that be true?”

Pierre looked away. “Those of us who are at risk for Huntington’s live our lives based on the presumption that they might be cut short. We often give up things because of that. I — before you, I hadn’t been involved with a woman for nine years, and, to be honest, I didn’t think I ever would be again.”

Molly nodded, as if a mystery had finally been explained. “This is why you’re so driven,” she said, her blue eyes wide. “Why you work so hard.”

Pierre returned the nod. “But when you’ve made sacrifices and then discover they were unnecessary, the regret can be too much to bear. That’s why even some of those who discover they don’t have the disease end up killing themselves.” He was quiet for a long time. “But now — now, it isn’t just me. I guess I should have the test.”

Molly reached out and stroked his cheek. “No,” she said. “No. Don’t do it for me. If you ever want to take it, do it for yourself. I was serious: I want to marry you and, if you do turn out to have the disease, we’ll deal with that at the time. My proposal wasn’t contingent on your taking the test.”

Pierre blinked. He was close to tears. “I’m so lucky to have found you.”

She smiled. “I feel the same way about you.”

They held each other tightly. When their embrace ended, Pierre said, “But I don’t know — maybe I should take the test anyway. I did do what you asked, you know: I met with someone from Condor Health a couple of weeks ago. But I couldn’t get a policy.”

“You still don’t have health insurance?”

Pierre shook his head. “See, right now, they’d reject me based on my family history. But in two months, on New Year’s Day, a new California law comes into effect. It doesn’t bar the use by insurance companies of family-history information, but it does bar the use of genetic info, and the latter takes precedence over the former. If I take the test for Huntington’s, regardless of the results, then they have to insure me; they can’t even charge me a higher premium, so long as I have no symptoms.”

Molly was quiet for a moment, digesting this. “I meant what I said: I don’t want you to take the test for me, and, well — if you can’t get insurance down here, we could move to Canada, no?”

“I — I suppose. But I don’t want to leave LBL; being here is the opportunity of a lifetime.”

“Well, there are thirty million Americans without health insurance. But they mostly manage—”

“No. No, it’s one thing to let you risk being married to someone who might become very sick; it’s quite another to ask you to additionally risk financial ruin. I should have the test.”

“If you think it’s best,” said Molly. “But I’ll marry you either way.”

“Don’t say that now. Wait till we have the test results.”

“How long will that take?”

“Well, normally a lab requires you to go through months of counseling before they’ll administer the test, to make sure you really want to take it and are going to be able to deal with the results. But…”

“Yes?”

Pierre shrugged. “It’s not a hard test — no harder than any other genetic test. As I said, I could do it myself in my lab at LBL”

“I don’t want you to feel pressured into doing this.”

Pierre shrugged. “It’s not you doing the pressuring; it’s the insurance company.” He was quiet for a while. “It’s all right,” he said finally. “It’s time I found out.”

“Explain what’s going on to me,” said Molly, sitting on a stool in Pierre’s lab. It was ten o’clock on a Saturday morning. “I want to understand exactly what’s happening.”

Pierre nodded. “Okay,” he said. “On Thursday, I extracted samples of my DNA from a drop of my own blood. I separated out my two copies of chromosome four, snipped off particular segments using special enzymes, and set about making radioactive images of those segments. It takes a while to develop those images, but they should be ready now, so we can actually check what my genetic code says in the specific gene associated with Huntington’s disease. That gene contains an area called IT15 — ‘interesting transcript number fifteen,’ a name given to it back when people didn’t know what it was for.”

“And if you’ve got IT15, you’ve got Huntington’s?”

“It’s not as simple as that. Everybody has IT15. Like all genes, IT15’s job is to code for the synthesis of a protein molecule. The protein IT15 makes has recently been dubbed ‘huntingtin.’ ”

“So if everyone has IT15,” said Molly, “and everybody’s body produces huntingtin, then what determines whether you have Huntington’s disease?”

“People with Huntington’s have a mutant form of IT15, which causes them to produce too much huntingtin. Huntingtin is crucial to organizing the nervous system in the first few weeks of an embryo’s development. It should cease to be produced at a certain point, but in those with Huntington’s disease it isn’t, and that causes damage to the developing brain. In both the normal and mutant versions of IT15, there’s a run of repeating nucleo-tide triplets: cytosine-adenine-guanine, or CAG, over and over again. Well, in the genetic code, each nucleotide triplet specifies the production of one specific amino acid, and amino acids are the building blocks of proteins. CAG happens to be one of the codes for making an amino acid called glutamine. In healthy individuals, IT15 contains between eleven repeats and thirty-eight repeats of this CAG triplet. But those who have Huntington’s disease have between forty-two and a hundred or so CAG repeats.”

“Okay,” said Molly, “so we look at each of your chromosome fours, find the beginning of the run of CAG triplets, then simply count the number of repeats of that triplet. Right?”

“Right.”

“You’re sure you want to go through with this?”

Pierre nodded. “I’m sure.”

“Then let’s do it.”

And they did. It was painstaking work, carefully examining the autoradiograph film. Faint lines represented each nucleotide. Pierre used a felt-tipped marker to write in the letters beneath each triplet: CAG, CAG. Molly, meanwhile, tallied the number of repeats on a sheet of paper.

Without blood samples from Elisabeth Tardivel and Henry Spade, there was no easy way to tell which of his chromosome fours had come from his father, so he had to check them both. On the first one, the string of CAG triplets ended after seventeen repeats.