Here is Ekaterin, and here is Nikki! That is the entire subset. How convenient.

"That's good, maybe this one will stick," says Linya encouragingly. "How about you, Nikki, what's up with you?"

Nikki ponders this question, then says, "I like your lightflyer!"

"I like it too! I learned to fly it just a couple of years ago and it's lots of fun."

"I bet," says Nikki. "Can I fly it too?"

"I don't think so, but you can sit on my lap on the way back to your house and see up close how I do it," she says. She has much longer arms than he does and can if necessary operate the thing one-handed, if he proves intractably handsy with the controls. "If you watch close enough, enough times, then you'll know how."

Nikki thinks this through, then says, "Okay." (His mama smiles.)

"I bought a replicator yesterday. They're cheaper than I expected," Linya remarks to Ekaterin. "Unless, of course, I wind up buying another one because we postpone Aral Adri for years and it's obsolete by the time we're ready."

"Do they go obsolete that fast? Or do you just have very high standards?"

"They haven't changed that much in the last couple hundred years, but nothing says that someone brilliant couldn't revolutionize the state of the art next month."

"What would a revolutionized uterine replicator even look like...? They're already revolutionary enough for me."

"If I knew what the next generation of replicators would be able to do, do you think I wouldn't be trying to invent it myself before someone else gets there?"

"Well. No," she says. "Of course you would be doing exactly that."

"But I found one that has a feature list I'm happy with - I won't bore you with the details of the chemical environment settings - and it'll be on its way from Escobar soon."

"Good. I didn't even know there was that much difference between - I mean, features? That's the sort of thing I'd expect to hear about a new - a new lightflyer, not a new womb."

"They're complicated machines. They differ in how you insert the zygote and how you decant the baby, and in how much fine control they can offer with respect to what the embryo's floating around in which I want particularly because I know a lot of genetic details and how those will interact with the replicator environment. They vary in how the placenta attaches when it forms, which as near as I can tell makes no difference to anything, and tolerance for environmental variation, which can - the ones sold on Beta Colony have to handle extreme exterior heat in case the air conditioning breaks, you don't want an entire batch of babies in progress wrecked because your air conditioning tech didn't show up; there are versions billed as being particularly earthquake-tolerant too!"

"That's amazing. So you wanted one with... fine control, but you didn't need it especially heatproof or earthquake-proof?"

"Right. Although I did get one rated for a fair amount of cold, in case something goes wrong with the heat. I could probably fix most things that might go wrong with the climate control, but I cannot teleport parts from wherever they are sold to my house, so if something particularly troublesome broke..."

"That makes sense. I'd never considered before how... in moving from the uterus to the replicator, you're not just getting rid of one set of problems, you're introducing new ones too. I never had to worry about - ordering replacement parts."

"The replicators themselves avoid needing replacement parts. They're designed for extreme robustness and redundancy," says Linya. "But, yes - in order to be adopted they couldn't even be just as good at growing a tiny human without letting the exterior environment do the tiny human any harm as the human body is. The human body isn't actually very good at that, although most miscarriages in populations that do body-birth are far too early to notice. A replicator has to get it right pretty much every single time from zygote all the way to decanting in order to look like a good idea."

"...Yes, I suppose that's true."

"It's an interesting chapter of history. I'm really curious about how Barrayar will adapt, as it's effectively the only planet that's been insulated from the technology in its early-adopter stage... are you planning on Nikki having any little brothers or sisters?"

"Oh - not yet," she says. "He's enough of a handful by himself." She is in fact holding Nikki's hand; she squeezes it. He makes a face, but then smiles, at this display of parental affection.