Why do they say "No" EVERY TIME I try to get them to have kids?! What can I do to change their minds?

Are they arguing or saying that it's too soon? For arguing, just keep trying. If they say it's too soon, my posts in this thread will explain what's happening.

I am facing the same problem too.
Put them together just argue. Right now i have 2 children. both also 5 years old.

I answered your question in your other post.