@ddljohn-- Well, no. There needs to be enough population to drive production. If there aren't enough people in a country, then production will go down. The economy will not grow and this will have a negative affect on economic development. This is the major reason why Western nations with low birthrates are allowing migrants. Because they want to make sure that there are enough workers for economic development to be sustained.
Population is such a difficult thing to control though. You can't force people to have more children and it's actually very difficult to force people to have fewer children too. China has been relatively successful with this but India, another very populated country, has not. And like we said, Western nations are increasingly relying on immigrants for their work force.