Credit: Jamie Tufrey

They called the ships storks, though they didn't look anything like the birds. Callisa's was a sphere and the ship was its own engine or, more correctly, billions of engines – nanoscale field emission thrusters covered it, like pores on skin.

Calissa ran her fingers over its surface, expecting it to feel rough like a shark's skin, but it was as smooth and soft as her face.

The case of 6,000 embryos she would be taking with her was already enwombed within the Stork, and the Stork was cradled within the belly of the Wombstation Adelaide, a long glittering tube spinning steadily in the darkness of space as it orbited Earth. Wombs within wombs.

The Stork's doorifice was tantalisingly open, but she couldn't enter her ship yet, which was vexing. Bloody irritating in fact. Calissa wrinkled her nose; the hold smelled of ozone and fresh paint. The holographic projection of the W. Adelaide, looking like an old school principal in a suit, took the simulation of a deep breath.

"Calissa, as is protocol, I must ask you again. Are you sure and certain that you wish to undertake this delivery to the Regent System colony, knowing full well its dangers, and all that you must leave behind?"

Calissa smiled; all these formalities. It was still not unheard of for families to litigate against AIs, should something go wrong. Not that her family had the resources to marshal a decent team of lawyers, but there were some organisations that funded such cases. "I am a midwife. I've devoted the last 10 years to this. Of course I'm bloody sure."

Yet another simulated AI sigh. "We know full well that you are a midwife, but that still does not preclude you from doubt or fear or second thoughts. Even after the appraisals."

Because sometimes they got it wrong. This was her last chance to quit. Behind her was a door; she need only turn her back on all her training, all her dreams. It was open to her, and she considered it, but as little more than an abstract proposition. She had passed through so many other doors to get to this singularity in her life at which only she and the AI and the Stork remained.

"I'm aware of all the factors, but I'm fine." Callisa could feel the AI's doubt. It read her body, knew her intimately, her blood pressure, heart rate, galvanic skin response, all were available to it. Nosy machines. Her fingers brushed the surface of the Stork again, annoyed that such an exultant moment should be given so much scrutiny. "OK, I have fears, but I have hopes. I'm also excited. This is the task I have chosen of my own will."

There was another interminable pause, perhaps to give her a chance to take it all back and run from the Stork and out that door. She did not. "So be it. Callisa Makepeace, you have now been transferred into the care of Stork 1787a. Good luck."

"Thank you," Callisa said. "Thank you." At last, she thought. The projection of the Wombship smiled, then blinked out.

Callisa slipped through the Stork's doorifice into the narrow confines of the ship proper. Confines was right. The doorifice closed, and the cockpit of the Stork wrapped around her like a spider with many legs … cold legs. She shivered as tubes punctured her flesh. These were mechanical umbilici that measured, assessed, and fed, and not just nutrients: data flooded her vision.

Storks were high-end in their processing power, the quality was exceptional, far better than she'd ever had in her dorm. She might be crammed in a space barely large enough for her to take a deep breath, but the Stork's data feed provided her with a world. The Stork was an icon in the corner of her vision. She winked at it.

Grinning at all that virtual space, she called up a few of her favourite things: an Albrecht Dürer self-portrait, an old image of her mother and father. Setting up a virtual data-space always took a while, getting the desktop properly cluttered, making everything feel lived-in. The Stork gave her time to do it.

Callisa faintly felt the Stork being slingshot from the Adelaide. Numbers spilled from the Stork's icon, describing all the things that the g-forces were doing to her body. She blinked them off. The system would let her know if there was a problem.

When she was done, the Stork's icon expanded. A generic AI avatar, a man in a bowler, bowed. "Welcome, Callisa," the Stork said warmly. "I have downloaded your files, and I see that you like chess."

Callisa grinned. "Is that a challenge?" A virtual chessboard appeared. "Go easy on me," she said. "I like chess, but it doesn't mean I'm good."

"Well, I am very good, but I am also in charge of eight tonnes of spaceship. My concentration is somewhat fractured."

Obviously not enough. The Stork beat her 14 times. The 15th game was a stalemate. The 16th she won.

Callisa didn't know how to give up. She had graduated at the top of her class, then gone on to blitz her extrasolar studies. All her life had been devoted to getting here: to getting on a Stork, the ultimate piloting gig.

She had let lovers and family slide to become a midwife – what an antiquated term, there was pretty much a 50-50 split, male/female, for the job – the human face of the embryocolonisation of the galaxy.

As they played chess, the ship hurtled from the wombstation, toward the Gate. The Gate was a tangle of wormholes, open mouths leading to the 400 terraformed worlds (402, the Stork updated her). Huge sub-light generation ships had trailed the wormholes behind them like silk. In another few decades some of those ships would be back, creating, on the other edge of the Solar System, another gate. Then interstellar travel would become a lot quicker. But that wasn't the way of it now.

Colonisation was a four-step process. First the worlds were found, then terraformed, a process taking decades in some cases. When the wormhole carrier ship reached its destination, the colony ships were sent out. On their arrival the first Stork was sent along the wormhole. Seventeen years later, the second Stork followed. Callisa's Stork was the first one for the Regent System, the 700th Stork launched.

Days passed, and weeks, radio frequencies buzzing with gate-bound craft, Storks and other ships, all on the one-way trips.

Stork 1787b's engines fired, launching bursts of nanoparticles into space – precise squirts of intricately shaped matter that shifted the Stork this way and that, so that it struck the Gate at exactly the right point.

Travelling through wormholes was both an exact and inexact science. The maths was gruesomely complicated, fooling the universe as to the ship's length, or more specifically the distance between two points of its length, as well as its mass.

Even so, the Storks were at the upper limit, in size and mass, for wormhole travel. Strike the target wormhole mouth at the wrong speed and the wrong angle and you could end up light-years off target, or, most likely, torn into a spiralling trail of exotic particles.

The Stork hit it perfectly.

Things only started to go wrong afterwards.

After a moment they were where they wanted to be, shooting out of a wormhole 40 light-years from Earth, the Stork firing squirts of nanocarbon in braking bursts, mass decreasing alarmingly (though not as rapidly as Callisa's pieces on the chessboard) as it used up its own matter to fuel the nano-squirts. Eight tonnes down to 6.5.

"The Regent System," the Stork announced. "Twelve planets, mostly gas giants, and one rocky body, Earth-like and ready to take those embryos. Hmm, that's odd."

The Stork went silent, the virtual chessboard disappeared.

"Stork," Callisa said, "What's wrong?"

"The Regency Darling isn't responding to my signals."

She had studied the Regency Darling, and was as familiar with its structural peculiarities as with her own Stork's. It looked like a dumbbell, two spheres linked by a long cylinder. Both spheres generated the arc of a magnetospheric plasma sail. The bulk of the ship contained the helium used to feed the sail.

The process was simple: the Regency Darling blew a big bubble of magnetically charged plasma, and solar winds drove it on, accelerating the ship slowly but steadily out of the system.

When the Regency reached its destination, it blew another bubble and this system's solar winds slowed her. Elegant as sailing ships, but none of that messing about in the rigging. It also burned through less matter than the Stork's propulsion system, even if it wasn't as precise in its steering.

Its crew had done the hard yards. Callisa and the Stork had merely swung in on its coat-tails. Travelling in space is dangerous. The constant streams of radiation, the dangers of striking particles at speeds close to light, their mass immensely multiplied by velocity. Wormhole travel was dangerous, but regular space travel was akin to travelling down the wrong side of the highway late at night with the lights off while wearing a blindfold.

The odds of dying were high; almost 30 per cent of those who travelled out of system perished. But the wormholes were small, you couldn't run a ship through them any larger than a Stork, which meant that most of the crew and matter needed for colonisation, including the other end of the wormhole, had to be carried at a quarter of light speed by the colony ship, hoping nothing lethal was in its way.

The colony ship was whole, but everything on it, Callisa saw now, was dead, even the ship's AI – self-terminated, the Stork told her, after searching the AI's data-necrosphere.

Why? How? Tragically bad timing, that was all. The magfield had ruptured, nothing fatal and easily repaired. But one of the benefits of magfields is the protection they offer from radiation. The Regency Darling was opened to any stray burst of lethal radiation. Before the AI could generate another field, the Regency Darling had encountered a fatal gamma ray burst, or some other deadly remnant of a star's demise.

Just bad luck, but deadly. There were no redundant systems in play, no back-up storm shelters, and the attempt to construct one had come too late. Within days the crew was gone, the ship silent. The Regency Darling's AI had survived that silence for a dozen years, getting the ship into the system and orbit, but finally burned out its circuits in its grief.

Callisa walked through a crypt. Dead children were wrapped in their parents' arms. She knew what she must do.

She was a midwife, she had a delivery to make.

"Can we do this?" she asked the Stork. "I'm a midwife, not a mother."

"I'm a Stork, not a colony AI."

"At least we're not alone in all of this."

The Stork uploaded a copy of itself into the ship, which decided within microseconds on the name Regency Stork. The Regency Stork contained 580 droids, everything from wall cleaners to external structural scuttlers.

All the tech that had been devoted to building a world was now turned to raising its population. The embryos were defrosted, enwombed, and umbilicated. Callisa spent the nine-month gestation getting ready. Then came the hard part.

The stage two stork came through the wormhole at the assigned moment; the Regency Stork guided it in. Callisa couldn't believe that 17 years had passed so quickly. Bloody hell, she thought, I'm getting old.

A man exited the doorifice, tall and handsome and utterly confused. "What is this place? Where is everybody? My Stork started chatting with the Regency AI, and decided I was better off waiting until we'd docked."

Stork smiled at Callisa. "Shall you tell him, or shall I?"

"There's always the museum," Callisa said.

She'd tried to gather them together, but her kids were so flighty. Well, you couldn't really call them kids any more, but that's what they'd always be to her. She didn't know if any other entire population had been raised largely by AI before this.

By the time they were three, they were fluent in eight languages, two of those binary based. Stork was a good teacher; if their joint parenting skills were somewhat eccentric, well, they'd done the best they could.

When the children were 11, they constructed Regency City, but quickly grew bored with it. The sky was the limit and the sky was what they sought. In their early teens, the kids had wrapped the planet and inner and outer systems with wormholes, then started exploring other worlds.

Even now, a few of them were racing toward Earth, desperate to check out the old world, maybe pass on some of the new tech.

One of the things her kids had constructed was the Regency Memorial, the story of the ship and her crew. That had been the singular event that set them off with all the determination of kids and teens, to explore and to do it right. Their craft were weird combinations of technology, elements of the Stork's thrusters and magnetic propulsion devices, new redundancy systems, new ways of dealing with radiation.

"Yeah, let's start with the museum." She grabbed the midwife's hand. He was gorgeous, and it gave her pleasure to hold an adult's hand. "It's a sad story, but it's not all grim. Only at the beginning. The kids, they've gone exploring. Not all of them, though." "Who's going to raise my embryos?" the midwife demanded, and then it seemed to sink in. "Oh."

Callisa smiled. "Just you and me and the machines, kiddo, maybe some of the more mature kids of the first gen. You see, out here, maybe in most parts of the galaxy, the midwife's job doesn't stop with the Delivery."

The midwife turned toward her. "Surely at least a few of the children wanted to see me," he said, his tone faintly nettled.

"Of course, of course – but it's only nine in the morning here. You'll get to see some of my kids soon enough, when they get out of bed." She shrugged. "Teenagers, what are you going to do?"