I don't think anyone can answer this question for anyone else.
We have five children - 11, 9, 6, 4 & 2. We are quite happy. We did not plan to have five, but are so glad we have our "surprise". :) I would welcome more, and we plan to adopt.
Some of my friends do not want any children. Others only want two, and have only wanted two for most of their lives.
If someone finds themselves with a "surprise" -- you'll be amazed at the joy the addition brings. Even in "bad" circumstances. One of my God-sons was conceived by rape (by her older sister's boyfriend - Yes, he is in jail) -- and the mom was 13. Nathan is now eight, and his birth mom raised him. She married a couple of years ago, and is quite happy. That's not to say there weren't struggles -- bc there have been. But, everything has always worked out.. .
I think your answer has to be answered by each couple/potential parent...