He can't quite make sense of Ned's reaction, the combination of emotions. He's unwittingly touched on something delicate again.

"Two," Daneel says after a moment's thought; it seems a proper number, to him. Enough to sustain the population, not enough to be excessive. "And they were very good parents. They were kind and generous, and their wisdom served them well. Their children were too young to remember their biological parents, but they grew up happy and well."

It's the best way he can think of the mitigate the unpleasantness of the parents' death.