I thought I would have my say in this topic.
Myself, I never thought i would have more than 1-2 children. I had No.1 when I was 20 and now I am expecting No.6 and I have just turned 30. This is definately my last one as even though DH is 6 yrs younger than me, by the time we are in our late 40's-early 50's, our children will be pretty much in their teens.