"So am I," I a.s.sured her. "That's a good sign. Everything worth doing is terrifying."

"But not everything terrifying is good."

I rolled over and lay beside her. She said, "On one level, it's easy. What greater gift could you give a child than the power to make real decisions? What worse fate could you spare her from than being forced to act against her better judgment, over and over? When you put it like that, it's simple.

"But every fiber in my body still rebels against it. How will she feel, knowing what she is? How will she make friends? How will she belong? How will she not despise us for making her a freak? And what if we're robbing her of something she'd value: living a billion lives, never being forced to choose between them? What if she sees the gift as a kind of impoverishment?"

"She can always drop the shielding on the Qusp," I said. "Once she understands the issues, she can choose for herself."

"That's true." Francine did not sound mollified at all; she would have thought of that long before I'd mentioned it, but she wasn't looking for concrete answers. Every ordinary human instinct screamed at us that we were embarking on something dangerous, unnatural, hubristic-but those instincts were more about safeguarding our own reputations than protecting our child-to-be. No parent, save the most willfully negligent, would be pilloried if their flesh-and-blood child turned out to be ungrateful for life; if I'd railed against my own mother and father because I'd found fault in the existential conditions with which I'd been lumbered, it wasn't hard to guess which side would attract the most sympathy from the world at large. Anything that went wrong with our child would be grounds for lynching-however much love, sweat, and soul-searching had gone into her creation-because we'd had the temerity to be dissatisfied with the kind of fate that everyone else happily inflicted on their own.

I said, "You saw Zelda today, spread across the branches. You know, deep down now, that the same thing happens to all of us." "Yes." Something tore inside me as Francine uttered that admission. I'd never really wanted her to feel it, the way I did.

I persisted. "Would you willingly sentence your own child to that condition? And your grandchildren?

And your great-grandchildren?"

"No," Francine replied. A part of her hated me now; I could hear it in her voice. It was my curse, my obsession; before she met me, she'd managed to believe and not believe, taking her acceptance of the multiverse lightly.

I said, "I can't do this without you."

"You can, actually. More easily than any of the alternatives. You wouldn't even need a stranger to donate an egg."

"I can't do it unless you're behind me. If you say the word, I'll stop here. We've built the Qusp.

We've shown that it can work. Even if we don't do this last part ourselves, someone else will, in a decade or two."

"If we don't do this," Francine observed acerbically, "we'll simply do it in another branch."

I said, "That's true, but it's no use thinking that way. In the end, I can't function unless I pretend that my choices are real. I doubt that anyone can."

Francine was silent for a long time. I stared up into the darkness of the room, trying hard not to contemplate the near certainty that her decision would go both ways.

Finally, she spoke.

"Then let's make a child who doesn't need to pretend."

2031.

Isabelle Schib welcomed us into her office. In person, she was slightly less intimidating than she was on-line; it wasn't anything different in her appearance or manner, just the ordinariness of her surroundings. I'd envisaged her ensconced in some vast, pristine, high-tech building, not a couple of pokey rooms on a back-street in Basel.

Once the pleasantries were out of the way, Isabelle got straight to the point. "You've been accepted," she announced. "I'll send you the contract later today."

My throat constricted with panic; I should have been elated, but I just felt unprepared. Isabelle's group licensed only three new adai a year. The short-list had come down to about a hundred couples, winnowed from tens of thousands of applicants. We'd traveled to Switzerland for the final selection process, carried out by an agency that ordinarily handled adoptions. Through all the interviews and questionnaires, all the personality tests and scenario challenges, I'd managed to half-convince myself that our dedication would win through in the end, but that had been nothing but a prop to keep my spirits up.

Francine said calmly, "Thank you."

I coughed. "You're happy with everything we've proposed?" If there was going to be a proviso thrown in that rendered this miracle worthless, better to hear it now, before the shock had worn off and I'd started taking things for granted.

Isabelle nodded. "I don't pretend to be an expert in the relevant fields, but I've had the Qusp's design a.s.sessed by several colleagues, and I see no reason why it wouldn't be an appropriate form of hardware for an adai. I'm entirely agnostic about the MWI , so I don't share your view that the Qusp is a necessity, but if you were worried that I might write you off as cranks because of it," she smiled slightly, "you should meet some of the other people I've had to deal with.

"I believe you have the adai's welfare at heart, and you're not suffering from any of the superst.i.tions-technophobic or technophilic-that would distort the relationship. And as you'll recall, I'll be ent.i.tled to visits and inspections throughout your period of guardianship. If you're found to be violating any of the terms of the contract, your license will be revoked, and I'll take charge of the adai."

Francine said, "What do you think the prospects are for a happier end to our guardianship?"

"I'm lobbying the European parliament constantly," Isabelle replied. "Of course, in a few years' time several adai will reach the stage where their personal testimony begins contributing to the debate, but none of us should wait until then. The ground has to be prepared." We spoke for almost an hour, on this and other issues. Isabelle had become quite an expert at fending off the attentions of the media; she promised to send us a handbook on this, along with the contract.

"Did you want to meet Sophie?" Isabelle asked, almost as an afterthought.

Francine said, "That would be wonderful." Francine and I had seen a video of Sophie at age four, undergoing a battery of psychological tests, but we'd never had a chance to converse with her, let alone meet her face to face.

The three of us left the office together, and Isabelle drove us to her home on the outskirts of the town.

In the car, the reality began sinking in anew. I felt the same mixture of exhilaration and claustrophobia that I'd experienced 21 years before, when Francine had met me at the airport with news of her pregnancy. No digital conception had yet taken place, but if s.e.x had ever felt half as loaded with risks and responsibilities as this, I would have remained celibate for life.

"No badgering, no interrogation," Isabelle warned us as she pulled into the driveway.

I said, "Of course not."

Isabelle called out, "Marco! Sophie!" as we followed her through the door. At the end of the hall, I heard childish giggling, and an adult male voice whispering in French. Then Isabelle's husband stepped out from behind the corner, a smiling, dark-haired young man, with Sophie riding on his shoulders. At first I couldn't look at her; I just smiled politely back at Marco, while noting glumly that he was at least 15 years younger than I was. How could I even think of doing this, at 46? Then I glanced up, and caught Sophie's eye. She gazed straight back at me for a moment, appearing curious and composed, but then a fit of shyness struck her, and she buried her face in Marco's hair.

Isabelle introduced us, in English; Sophie was being raised to speak four languages, though in Switzerland that was hardly phenomenal. Sophie said, "h.e.l.lo" but kept her eyes lowered. Isabelle said, "Come into the living room. Would you like something to drink?"

The five of us sipped lemonade, and the adults made polite, superficial conversation. Sophie sat on Marco's knees, squirming restlessly, sneaking glances at us. She looked exactly like an ordinary, slightly gawky, six-year-old girl. She had Isabelle's straw-colored hair, and Marco's brown eyes; whether by fiat or rigorous genetic simulation, she could have pa.s.sed for their biological daughter. I'd read technical specifications describing her body, and seen an earlier version in action on the video, but the fact that it looked so plausible was the least of its designers' achievements. Watching her drinking, wriggling and fidgeting, I had no doubt that she felt herself inhabiting this skin, as much as I did my own. She was not a puppeteer posing as a child, pulling electronic strings from some dark cavern in her skull.

"Do you like lemonade?" I asked her.

She stared at me for a moment, as if wondering whether she should be affronted by the presumptuousness of this question, then replied, "It tickles."

In the taxi to the hotel, Francine held my hand tightly.

"Are you OK?" I asked.

"Yes, of course."

In the elevator, she started crying. I wrapped my arms around her.

"She would have been 20 this year."

"I know."

"Do you think she's alive, somewhere?"

"I don't know. I don't know if that's a good way to think about it."

Francine wiped her eyes. "No. This will be her. That's the way to see it. This will be my girl. Just a few years late."

Before flying home, we visited a small pathology lab, and left samples of our blood.

Our daughter's first five bodies reached us a month before her birth. I unpacked all five, and laid them out in a row on the living room floor. With their muscles slack and their eyes rolled up, they looked more like tragic mummies than sleeping infants. I dismissed that grisly image; better to think of them a.s.suits of clothes. The only difference was that we hadn't bought pajamas quite so far ahead.

From wrinkled pink newborn to chubby 18-month-old, the progression made an eerie sight-even if an organic child's development, short of serious disease or malnourishment, would have been scarcely less predictable. A colleague of Francine's had lectured me a few weeks before about the terrible "mechanical determinism" we'd be imposing on our child, and though his arguments had been philosophically naive, this sequence of immutable snapshots from the future still gave me goose b.u.mps.

The truth was, reality as a whole was deterministic, whether you had a Qusp for a brain or not; the quantum state of the multiverse at any moment determined the entire future. Personal experience-confined to one branch at a time-certainly appeared probabilistic, because there was no way to predict which local future you'd experience when a branch split, but the reason it was impossible to know that in advance was because the real answer was "all of them."

For a singleton, the only difference was that branches never split on the basis of your personal decisions. The world at large would continue to look probabilistic, but every choice you made was entirely determined by who you were and the situation you faced.

What more could anyone hope for? It was not as if who you were could be boiled down to some crude genetic or sociological profile; every shadow you'd seen on the ceiling at night, every cloud you'd watched drift across the sky, would have left some small imprint on the shape of your mind. Those events were fully determined too, when viewed across the multiverse-with different versions of you witnessing every possibility-but in practical terms, the bottom line was that no private investigator armed with your genome and a potted biography could plot your every move in advance.

Our daughter's choices-like everything else-had been written in stone at the birth of the universe, but that information could only be decoded by becoming her along the way. Her actions would flow from her temperament, her principles, her desires, and the fact that all of these qualities would themselves have prior causes did nothing to diminish their value. Free will was a slippery notion, but to me it simply meant that your choices were more or less consistent with your nature-which in turn was a provisional, constantly-evolving consensus between a thousand different influences. Our daughter would not be robbed of the chance to act capriciously, or even perversely, but at least it would not be impossible for her ever to act wholly in accordance with her ideals.

I packed the bodies away before Francine got home. I wasn't sure if the sight would unsettle her, but I didn't want her measuring them up for more clothes.

The delivery began in the early hours of the morning of Sunday, December 14, and was expected to last about four hours, depending on traffic. I sat in the nursery while Francine paced the hallway outside, both of us watching the data coming through over the fiber from Basel.

Isabelle had used our genetic information as the starting point for a simulation of the development in utero of a complete embryo, employing an "adaptive hierarchy" model, with the highest resolution reserved for the central nervous system. The Qusp would take over this task, not only for the newborn child's brain, but also for the thousands of biochemical processes occurring outside the skull that the artificial bodies were not designed to perform. Apart from their sophisticated sensory and motor functions, the bodies could take in food and excrete wastes-for psychological and social reasons, as well as for the chemical energy this provided-and they breathed air, both in order to oxidize this fuel, and for vocalization, but they had no blood, no endocrine system, no immune response.

The Qusp I'd built in Berkeley was smaller than the Sao Paulo version, but it was still six times as wide as an infant's skull. Until it was further miniaturized, our daughter's mind would sit in a box in a corner of the nursery, joined to the rest of her by a wireless data link. Bandwidth and time lag would not be an issue within the Bay Area, and if we needed to take her further afield before everything was combined, the Qusp wasn't too large or delicate to move.

As the progress bar I was overlaying on the side of the Qusp nudged 98 percent, Francine came into the nursery, looking agitated.

"We have to put it off, Ben. Just for a day. I need more time to prepare myself."

I shook my head. "You made me promise to say no, if you asked me to do that." She'd even refusedto let me tell her how to halt the Qusp herself.

"Just a few hours," she pleaded.

Francine seemed genuinely distressed, but I hardened my heart by telling myself that she was acting: testing me, seeing if I'd keep my word. "No. No slowing down or speeding up, no pauses, no tinkering at all. This child has to hit us like a freight train, just like any other child would."

"You want me to go into labor now?" she said sarcastically. When I'd raised the possibility, half-jokingly, of putting her on a course of hormones that would have mimicked some of the effects of pregnancy in order to make bonding with the child easier-for myself as well, indirectly-she'd almost bit my head off. I hadn't been serious, because I knew it wasn't necessary. Adoption was the ultimate proof of that, but what we were doing was closer to claiming a child of our own from a surrogate.

"No. Just pick her up."

Francine peered down at the inert form in the cot.

"I can't do it!" she wailed. "When I hold her, she should feel as if she's the most precious thing in the world to me. How can I make her believe that, when I know I could bounce her off the walls without harming her?"

We had two minutes left. I felt my breathing grow ragged. I could send the Qusp a halt code, but what if that set the pattern? If one of us had had too little sleep, if Francine was late for work, if we talked ourselves into believing that our special child was so unique that we deserved a short holiday from her needs, what would stop us from doing the same thing again?

I opened my mouth to threaten her: Either you pick her up now, or I do it. I stopped myself, and said, "You know how much it would harm her psychologically, if you dropped her. The very fact that you're afraid that you won't convey as much protectiveness as you need to will be just as strong a signal to her as anything else. You care about her. She'll sense that."

Francine stared back at me dubiously.

I said, "She'll know. I'm sure she will."

Francine reached into the cot and lifted the slack body into her arms. Seeing her cradle the lifeless form, I felt an anxious twisting in my gut; I'd experienced nothing like this when I'd laid the five plastic sh.e.l.ls out for inspection.

I banished the progress bar and let myself free-fall through the final seconds: watching my daughter, willing her to move.

Her thumb twitched, then her legs scissored weakly. I couldn't see her face, so I watched Francine's expression. For an instant, I thought I could detect a horri-fied tightening at the corners of her mouth, as if she was about to recoil from this golem. Then the child began to bawl and kick, and Francine started weeping with undisguised joy.

As she raised the child to her face and planted a kiss on its wrinkled forehead, I suffered my own moment of disquiet. How easily that tender response had been summoned, when the body could as well have been brought to life by the kind of software used to animate the characters in games and films.

It hadn't, though. There'd been nothing false or easy about the road that had brought us to this moment-let alone the one that Isabelle had followed-and we hadn't even tried to fashion life from clay, from nothing. We'd merely diverted one small trickle from a river already four billion years old.

Francine held our daughter against her shoulder, and rocked back and forth. "Have you got the bottle? Ben?" I walked to the kitchen in a daze; the microwave had antic.i.p.ated the happy event, and the formula was ready.

I returned to the nursery and offered Francine the bottle. "Can I hold her, before you start feeding?"

"Of course." She leaned forward to kiss me, then held out the child, and I took her the way I'd learned to accept the babies of relatives and friends, cradling the back of her head with my hand. The distribution of weight, the heavy head, the play of the neck, felt the same as it did for any other infant. Her eyes were still screwed shut, as she screamed and swung her arms.

"What's your name, my beautiful girl?" We'd narrowed the list down to about a dozen possibilities, but Francine had refused to settle on one until she'd seen her daughter take her first breath. "Have you decided?" "I want to call her Helen."

Gazing down at her, that sounded too old to me. Old-fashioned, at least. Great-Aunt Helen. Helena Bonham-Carter. I laughed inanely, and she opened her eyes.

Hairs rose on my arms. The dark eyes couldn't quite search my face, but she was not oblivious to me. Love and fear coursed through my veins. How could I hope to give her what she needed? Even if my judgment had been faultless, my power to act upon it was crude beyond measure.

We were all she had, though. We would make mistakes, we would lose our way, but I had to believe that something would hold fast. Some portion of the overwhelming love and resolve that I felt right now would have to remain with every version of me who could trace his ancestry to this moment.

I said, "I name you Helen."

2041.

"Sophie! Sophie!" Helen ran ahead of us toward the arrivals gate, where Isabelle and Sophie were emerging. Sophie, almost 16 now, was much less demonstrative, but she smiled and waved.

Francine said, "Do you ever think of moving?"

"Maybe if the laws change first in Europe," I replied.

"I saw a job in Zurich I could apply for."

"I don't think we should bend over backward to bring them together. They probably get on better with just occasional visits, and the net. It's not as if they don't have other friends."

Isabelle approached, and greeted us both with kisses on the cheek. I'd dreaded her arrival the first few times, but by now she seemed more like a slightly overbearing cousin than a child protection officer whose very presence implied misdeeds.

Sophie and Helen caught up with us. Helen tugged at Francine's sleeve. "Sophie's got a boyfriend!

Daniel. She showed me his picture." She swooned mockingly, one hand on her forehead.

I glanced at Isabelle, who said, "He goes to her school. He's really very sweet."

Sophie grimaced with embarra.s.sment. "Three-year-old boys are sweet." She turned to me and said, "Daniel is charming, and sophisticated, and very mature."

I felt as if an anvil had been dropped on my chest. As we crossed the car park, Francine whispered, "Don't have a heart attack yet. You've got a while to get used to the idea."