Dakota Fanning. (Leon Bennett/WIREIMAGE)

But she’s not on the cover of just any magazine. She’s on the cover of February’s Cosmopolitan, the lady mag about sex, relationships, health and celebrities.

As you may be able to guess, teenager plus sex equals outrage.

A picture of the 17-year-old looking grown-up, yet sweet in a pink, sparkly dress is flanked on the cover by headlines including, “His Best Sex Ever” and “Too Naughty To Say Here But You Have To Try This Sex Trick.” Fanning is the magazine’s “Fun Fearless Female of the Year.”

Fox 411 spoke to Rachelle Friberg, a self-declared media expert and “conservative girl,” who said Cosmo was “going overboard by putting an underage girl on its cover.”

“It is one thing to educate young women about sex and their bodies, but putting a young, underage girl on the cover of a magazine that had long been known to push the limits is sending the wrong message,” she continued.

New York Magazine blogger Jenni Avins kind of agreed: “We don’t mean to be prude, but isn’t she like, 17?”

A rep for Cosmo defended the cover to Fox 411, calling Fanning “a mature, fearless young woman and we are proud to honor her.”

Though not prompted by Fanning’s issue, a petition on Change.org has been started to have Cosmo sold in non-transparent bags to no one younger than 18 in order to “protect young girls.” The petition, started by Nicole Weider of Project Inspired, a Web site covering “fashion, beauty, celebs, Jesus and inspiration,” currently has more than 14,000 signatures.

Fanning, who turns 18 in February, is the youngest celebrity to appear on the cover of Cosmo since at least 2000, according to an archive on the magazine’s site. But she’s isn’t by much.

Hayden Panettiere and Hilary Duff were 18 when they appeared on covers in 2008 and 2006, respectively. Keira Knightly was 19 on her 2004 cover, as was Kirsten Dunst in 2001. Similar objections to their covers couldn’t be located on the Internet.

Coincidentally, this cover controversy comes just two months after a Marc Jacobs perfume ad featuring Fanning was banned by a watchdog agency in Britain for sexualizing a child.

Do you think Fanning is too young to be a Cosmo cover girl? Tell us in the comments.