On children and expression and the Generations in particular: No Gestalts until graduation from Primary School. They've also traditionally been restricted in what they can commune with up to that point as well. So there is at least that little backstop on the House Karinne side of things. I'd expect they'd stick to that practice with resonant technology as well, not that it matters on Karsa at this point. They'll undoubtedly advise that the Faey and the Terran governments do the same(and have a decent chance of it being honored). Now when/if they obtain resonant tech and share it with the Confederation, whether
they honor that advice is another matter. But as to the expected age of a Generation and their expression of telepathy:
From
Secession(Book 5):
Outside of Jason’s own children, 51% of all the new Generation-born in the first wave of births had expressed, right around the age of 5.5 years on the average. Cybi had told him that that was about right for a Generation, so that didn’t make Rann or any other others too unusual, at least in the perspective of the House of Karinne and the history of the Generations.
Other tangential items: In
Subjugation(book 1) it also is explicitly mentioned
by Jason that "some races" engaged in genetic engineering to develop Telepaths of their own, often in direct response to encountering the Faey. While
that doesn't seem to ever be brought up again, Jason certainly spent plenty of time brooding about the Generations having been engineered to be what they are. That backstory as to the origins for a number of the telepaths that exist in the Galaxy is likely to come back in a significant way in the near-ish future I'm sure. As the Karinnes and Kimdori try to prevent the others from creating even more Generations for their own respective races. I'd almost be surprised if one or more of the leaders doesn't bring up that very fact in the "near future" (deliberately) where Jason can hear it.
And another potentially looming issue:
Tribulation (Book 4) had Jason contending with brain damage suffered as a consequence of having merged with Cybi. Jason was infected with viral therapy to heal the damage, the only other person who needed treatment was Rahne, as the only other Human Generation with a
Human synaptic pathway map. The ending of Book 4 is likely to be coming to Jason's attention in the coming months, as I suspect the humans who were hit with his mutated form of the retrovirus won't have to contend with that particular complication, but it is going to become quite rampant among the humans who were on the receiving end of the FMS version. That also would help explain
why it mutated after encountering him.
From
Tribulation(Book 4)
But at this time, the need for the projection of self was important. The large, black-furred Kereth stood beside her projection within the room, having delivered his final report to her in person, as she had commanded. He stood there with arms folded, tail swishing absently as he looked at the image of Jason, then glanced at Cybi. “You don’t have to worry about him, Cybi,” he assured her. “He may suffer an occasional minor headache, but no other side effects.”
“How long will it take?”
“Three to five months,” he replied. “If Songa catches it in its early stages, she might try to interfere.”
“I have access to her medical scanners. She will not catch it.”
“Just keep a close watch on him. You know how volatile Generation DNA can be when it’s forcibly manipulated. The long history of cancer in his family is a glaring indicator of that. Make sure you scan him for cancer at least once a week. It will appear quickly and spread like wildfire within him.”
“I will ensure he remains well. Thank you, Kereth.”
“I am ever at the service of a CBIM, my Lady,” he replied easily, then he was quiet a long moment. “Are you sure this was the right path? Perhaps we should have had Rahne undergo this procedure first? After all, they are the only two who are susceptible to being harmed by you in a merge. The children share Faey synaptic maps, they’re immune to the damage.”
“No. Jason is the most compatible with me. We have the strongest merge. For this to work, it had to be him. The safety of the house depends on it.”
. . .
It was from there that she began her vigil, watching her Grand Duke every second, keeping scanners on him to watch for any cancerous cells that appeared because of the Kimdori stem virus within him, slowly altering the DNA in every cell of his body in a very small, very subtle manner, correcting the minor genetic error that had caused her to harm him in the merge. It was a genetic flaw that Jason and Rahne shared, and a flaw that only Jason and Rahne suffered, that would cause them harm if they exerted too much power in a merge. Rahne too would undergo this therapy once Jason had completed it, and it would be done quietly, so Jason would not know about it.
He had forbade her to restart the Program. This was not the Program, but altering her Grand Duke’s DNA to heal him of the flaw that harmed him in the merge would certainly fall within those restrictions, should he know what she was doing. For his own good, she would keep this secret.
Her devotion to Jason as a friend and a Grand Duke was eclipsed only by her duty to the house. For the good of the house, this had to be done.
(Dahnai was already pregnant with Raisha well before Jason underwent the above mentioned treatment, so that genetic information would have been lacking from the database of the FMS.)