Based on something I read about how the birth rate crunch is actually a lot to do with smaller families not childfree people:
In your child's class what's the main number of siblings? I totted up for my reception child and it was about 22 kids were one of two, 3 only children and 5 as one of 3. Having two kids seems very much the norm. Obviously it's reception so there could be more siblings later. We are home counties, reasonably affluent.