This is fun to think about!
Both sets of my grandparents have a long line of boys ending in a girl (one side has 5 children, one has 4). I suspect the side with 5 would have stopped if they had gotten a girl sooner, the other side was happy to have children until my grandmother's disabilities made pregnancy dangerous.
My parents had 3 (didn't really want any though).
For my husband, one side had and wanted (and thinks people should only have) 1, though they adopted/took in another for a relative when they were older. His other side had 4, and like my side were happy (and were very happy to have all girls) to continue but his grandmother's health made them decide to not continue.
His mum and dad have 3, his stepdad had 2 but raised my husband as his third.
Both of us have one sibling with 1 child (and adamantly staying that way) and another who is firmly child-free.
We have three, would love to be blessed with more -- currently just hoping for a 4th, husband thinks 5-6 would be ideal, I waver depending on the day (I want 4, sometimes I think I want more than that). I find it very interesting we're so different from our siblings (yet have siblings so similar). I would say I would like a family like my grandparents with the 4 - who chose and prioritised family and were open to kids come what may - because they always seemed happy and satisfied together, even when my grandmother's health and disabilities got very bad.