This is what I said in the thread:
>*all children left their tribe at the age of seven to be raised in other tribes, not just in these islands but often on mainland Europe as well.
This sounds so unlikely, plus, it doesn't even make sense.
Yes, it was not unusual in many cultures for a sort of hostage exchange to take place for the children of ruling classes to take place. E.g. Little prince Alric of The Celts and Little Prince Benjamin of Judea are fostered in Rome, and grow up Roman, so that when they are now rulers of the Celts & Judeans, they think twice about waging war on Rome. Agreed.
But what you said: "all children left their tribe at the age of seven to be raised in other tribes, not just in these islands but often on mainland Europe as well."
Village AB: children Ann, Allan - children of the Adams & children Bella, Bob, children of the Binns.
Village XY: children Xander & Xanthe Xins, Yuri and Yana Yip.
At age 7, Ann and Allan go and live with the Xins, Bella and Bob go and live with the Yips in XY village.
And. Yuri and Xanthe live with the Adams, and Xander and Yana live with the Binns in AB village.
So what will end up happening is it is MORE likely you marry your sibling, having been split up from birth. Who is keeping track of siblings from different villages?
Plus if ALL the children are swapped, you are an AB village child, living in XY village with OTHER AB village children.
Plus, mothers DO NOT easily give up their children.
More likely is every few years there were big gatherings, people from different settlements mixed, widened the gene pool that way.