http://www.cis.org/articles/2005/back1105.html

I didn't cut and paste because the article is pretty long. But here are a couple of interesting points:

Immigrants Do Not Account for High U.S. Fertility. In a study in April of this year, we found that immigrants had little impact on the nation’s fertility.9 Using a different data source, we found that without immigrants the national fertility rate still would be two children on average. The 2002 ACS study shows the same basic results. If all the immigrants are removed from the data and the fertility rate recalculated, the overall fertility rates in the United States would still be about two children, or 2.05 children. It is true that America does have a higher fertility rate than other advanced industrialized democracies – 1.4 for Europe or 1.3 for Japan. But that higher rate is due almost entirely to native-born American women. For whatever reason, they have significantly more children on average than women in other western countries. It must be remembered that nearly eight out of 10 births in the United States are to native mothers, thus it is their characteristics that will primarily determine the overall fertility rate in the United States.


That's pretty interesting. Hmmmm...

And this, too:

Immigration Accounts for Most U.S. Population Growth. Although immigration has little effect on the nation’s overall fertility rate, new immigrants (legal and illegal) plus births to immigrants add some 2.3 million people to the United States each year, accounting for most of the nation’s population increase. In fact, because natives have only two children on average, absent the additions that come from immigrants, the U.S. population would be roughly stable in the long-run without continued high levels of immigration. Whatever one thinks about the costs and benefits of continued population growth, there is no question that immigration is the driving force behind it.


Okay, so given that, WHY IS OUR PRESIDENT PUSHING FOR MORE IMMIGRATION! This is the hard question we need to ask our leaders now.