The Hispanic population in the United States has had a big impact on the country's overall population growth due to their high fertility rates. Without Hispanics, the U.S. would have had lower birth rates similar to many European countries. Mexican and Central American Hispanics have the highest fertility rates, with Mexicans having the most significant impact. Other Hispanic groups like Cubans and Puerto Ricans have lower fertility rates compared to Mexicans. Overall, Hispanic women have more children on average than non-Hispanic white women, helping the U.S. population grow naturally.