The most recent figures show the United States is in the second year of a baby boomlet.
Researchers say more babies were born in the U.S. in 2007 than any year in its history. The growth tops the peak during the so-called ``baby boom'' more than 50 years ago.
The more-than-4.3 million births in 2007 mark another record: births to unwed mothers have reached 40 percent, an all-time high.
The numbers also show, on average, a U.S. woman has about 2 babies. That's the ``magic number'' required for a population to replace itself.
Overall, U.S. fertility rates are higher in every racial group, the highest being among Hispanic women. Among the states, Utah continues to have the highest birth rate and Vermont has the lowest.