More babies are conceived during December than in any other month in the United States, two University of Michigan researchers report.
Demographer David Lam and economist Jeffrey Miron found that birth rates 10 to 15 percent higher than other months typically are recorded in September, nine months later, Parenting magazine says.
Miron says there are several reasons for this, one of which is the "leisure time effect." Because most Americans have time off from work during the December holidays, couples have more free time to be together.
Another contributing factor, Miron notes, is the "warm family effect." As relatives gather, family members display their best behavior, and "those nieces and nephews start looking awfully cute," Miron says.