Guess which country has the lowest fertility rate — Iran or the United States. It’s Iran.
The United States is one of the few rich nations of the world in which women have more children during their child-bearing years (15 to 49) than it takes to replace them and the fathers. Iran has a fertility rate of 1.9 for the whole country, 1.5 for the capital city of Tehran. The magic number is 2.1. Two to replace the parents, point one to compensate for early female deaths. The U.S. rate is at 2.1 or a bit higher.