Why do people want to have children? Sooner or later most people will want to have children. What are some of the most common psychological reasons leading people to want to have children? What are their motivations and expectations?
There are many reasons why people want to have children :


Some want to have children because they hope it can save their declining marriage / relationship
Some want to have children because they feel instinctively driven towards it
Some want to have children because they feel they're supposed to
Some want to have children because they feel they're missing "something" in their lives
Some want to have children because they want to learn more about themselves
Some want to have children because they want to learn more about the man or woman they love
...


Still, I believe most reasons why people want to have children are perfectly captured by this single quote :


  Nevertheless, if you ask me, most people have children just as their
  own enthusiasm about life begins to wane. A child allows us to revisit
  the excitement we once felt about, well... everything. A generation
  later, our grandkids bump up our enthusiasm yet again. Reproducing is
  a kind of booster shot to keep us loving life.
  
  ― Chuck Palahniuk, Damned