OWBC Question...

Okay, I'm not sure about this - the no-promotions generation is defined in the rules as being "from birth to birth". The thing is, one of my gen 1 spares already had one kid (and has twins on the way too), while Olive, the gen 1 heiress, has just graduated college. Do the spare's children count as the gen 2 birth mentioned in the rules, or does that only apply for the gen 2 child(ren) Olive eventually gives birth to in the main house?