It turns out that mother's instinct is correct because Rose has twin boys at closer to ten months than nine (something Chris assures her is more than normal for his people, back before they used looms).

They name them Jack Michael and John Ian, and before anyone knows it they are calling the pair JJ, as if they already have their own celebrity nickname (in fact the newspapers may be where it came from).

Jack doesn't fuss at all, sleeping through the racket his younger brother causes, when even Donna (who sleeps like the dead) wakes up and goes into their room.

John constantly acts like he's being poked by something sharp, unless either his mother or his sister is holding him and Donna is so fascinated by these two younger siblings that Rose doesn't mind. (But still neither of will tell her where babies come from.)