Jacob continued a 12-year run as the most popular name for boys in 2010, according to the list released Thursday. Isabella was the most popular name for girls for a second year at the top.
Nearly 22,000 boys were named Jacob in 2010, followed by Ethan, Michael, Jayden and William. Nearly 23,000 girls were named Isabella, followed by Sophia, Emma, Olivia and Ava.
Names with different spellings were counted separately. For example, Aiden was No. 9 among boys, while Aidan was No. 94 and Aaden was No. 556. Among the girls, Chloe was No. 9 and Khloe was No. 42; Zoe was No. 31 and Zoey was No. 47.
Baby-naming experts said Americans are pulled by sometimes conflicting impulses when choosing names for their children. They gravitate toward the popular, wanting their child to fit in. But many also want their child's name to be unique, so they don't have to share it with four other kids in class at school.
Many turn to the Bible for inspiration, while others turn to popular culture and, increasingly, reality TV.
The fastest-rising names for both girls and boys came from a pair of reality TV shows called "16 and Pregnant" and "Teen Mom." Maci was the biggest riser among girls, jumping 423 spots to No. 232. Among boys, Bentley shot up 414 spots to No. 101. Maci Bookout has starred as a teen mother on the MTV shows. Her baby's name is Bentley.
"It certainly tends to say this is what people are watching and what they are connecting with," Astrue said. "I'll leave it to others to explain the phenomenon."
Laura Wattenberg, author of "The Baby Name Wizard," said reality TV stars can have a big influence on baby names because they remind viewers of regular people.
"We have this perception that Hollywood celebrities are on another planet because they choose weird names for their kids," said Wattenberg, who runs the website BabynameWizard.com. "The fact is, average Americans are just as creative, and when they find themselves on TV, they are even more influential about names."
Celebrity baby names have a better chance of catching on if soon-to-be parents are familiar with them, Wattenberg said. For example, Bentley, aside from being the name of a luxury automobile, is well known to fans of country music star Dierks Bentley.
"A celebrity can only launch a hit name if parents were already ready for it," Wattenberg said.
That might explain why Snooki hasn't made the list.
Baby names are getting more diverse, Wattenberg said. Three decades ago, a third of all babies had names that were in the top 20. Last year, only 14 percent of babies had names from the top 20. Religious names have endured -- and even received a new twist. Nevaeh, which is 'heaven' spelled backward, debuted in 2001 at No. 266. It is now more popular than ever, reaching No. 25 in 2010. Heaven, by the way, dropped 52 spots to No. 324.
Popularity can be fleeting; just ask the first family. Both Malia and Sasha -- the names of the Obamas' daughters -- were fast risers in 2009, the year President Barack Obama took office. Both names, however, plunged in 2010, with Malia dropping 111 spots, to No. 302, and Sasha dropping 84 places, to No. 344.
Wattenberg, however, said it is typical for names that quickly gain popularity to lose it just as quickly.
"That might look like bad news for Obama; it might look like a political statement," Wattenberg said. "But in fact it was just a one-year spike because of the news cycle."
She noted that Sasha and Malia were still more popular in 2010 than they were in 2008, the year Obama was elected.
The Social Security Administration provides lists of baby names on its website dating to 1880, when the top two names were John and Mary. The list, which includes top baby names by state, draws millions of people. The agency hopes that people go to the website to see the baby names and stay to learn about other services, Astrue said.