For the last decade, Americans in supermarket checkout lines have been inundated with the tabloid headlines: "Jen's finally PREGNANT!" "A Baby for Jen!" "Jen: Pregnant and Alone." "Jen's Baby Dream Shattered." "TWINS for Jen!"

Most people roll their eyes and move on — but after years of this nonsense, Jennifer Aniston had enough. The Emmy-winning actress, the subject of countless magazine covers declaring her pregnancy despite the fact that she's never had a baby, wrote a powerful essay in the Huffington Post on Tuesday that declared, "For the record, I am not pregnant. What I am is fed up."

Aniston, 47, went on to decry tabloid culture for pushing the offensive narrative that a woman isn't "complete" until she's a mother — as well as their constant body-shaming. It appeared to be a direct shot at In Touch Magazine, which last month published a cover proclaiming Aniston's "miracle" pregnancy, complete with a photo of the actress in a bikini and an arrow pointing to her stomach "bump." (Later, her publicist issued a tongue-in-cheek statement saying, "What you see is her having just enjoyed a delicious big lunch and her feeling safe on private property.")

Aniston's response is unusual, because she — like most Hollywood stars — generally doesn't dignify tabloid gossip. But in addition to the many cultural issues she addresses, her now-viral op-ed shines a light on two questions: How, exactly, do tabloids get away with this kind of thing? And really, why are people so fascinated over the status of Aniston's womb?

For the latter, you could go all the way back to the Greek gods — the higher powers that mere mortals looked to for guidance surrounding sex, marriage and childbearing. In modern culture, celebrities function in much the same way: With their wealth and beauty, they represent an irresistible yet unattainable way of life. At the same time, we like thinking that, deep down, these stars are really just like us — especially since we all have the same practical concerns about pregnancy and fertility.

"We're obsessed with celebrities when they become pregnant because it's a marriage of two absolutely extraordinary and mundane things," said Renée Ann Cramer, a professor at Drake University and author of "Pregnant With the Stars: Watching and Wanting the Celebrity Baby Bump."

Aniston fits that celebrity mold perfectly, Cramer said, given that she's a textbook Hollywood star: Beautiful, thin, witty, charismatic. And at the same time, due in large part to her "good girl" persona as Rachel Green on the iconic sitcom "Friends," women (the target tabloid magazine audience) look at Aniston and see a version of themselves, or their neighbor, or their best friend for whom they can't wait to throw a baby shower. She's just "Jen."

Plus, Aniston's personal life is uniquely suited to pregnancy speculation. Once known for relationships with Counting Crows frontman Adam Duritz or TV star Tate Donovan, her marriage to Brad Pitt in 2000 helped fuel her launch to superstardom, as they were known as the true golden couple. There was pregnancy speculation throughout their marriage, yet after they divorced in 2005, the common gossip was that she was too "career-focused" and Pitt wanted kids.

When Pitt started immediately dating Angelina Jolie and they had a baby soon after, Aniston — in what was known as the "poor Jen" trope — became a figure to be pitied. Not only had she "lost her man" to another woman, but they had a family. What could be sadder than that?

"In American history, women have been perceived to reach their height of moral perfectibility when they're pregnant and mothering," Cramer said. That cultural mind-set – specifically one focused on white women – means the actress, as Cramer puts it, "hasn't been able to reach the pinnacle of her goodness without that pregnancy."

After several relationships in the last decade (Vince Vaughn, John Mayer) Aniston met actor Justin Theroux around 2011, and last summer, they officially tied the knot. Gossip about Aniston's baby preoccupation didn't die down: Before In Touch's cover last month, OK! Magazine boasted pictures of a supposed Aniston baby bump. How are tabloids allowed to make the same claim over and over with no consequences or lawsuits? (In Touch magazine did not return a request for comment.)

Essentially, the law has evolved to make it more difficult for public figures to sue for libel. According to Virginia-based attorney Lee Berlik, it boils down to this: The law expects that if you're a public figure, people are going to talk about you. Most courts would hold that almost everything you do is newsworthy. For example: Whether you're pregnant, even though of course it's no one's business but your own.

As a result, tabloids have a longer leash — the law is more lenient about how much fact-checking reporters have to do. So if a tabloid reporter looks at Aniston's stomach and sees a bump, it could be argued that the reporter really thought she was pregnant.

"If you're a celebrity, in most cases, you need to prove that – to sue for libel – not only what was written about you was false, but that the person who wrote it or reported it knew that it was false and wasn't just making an innocent mistake," Berlik said.

Celebrities generally don't sue the tabloids because it's extremely difficult to prove that the publication knew what they were writing was false. To prove libel, they, like everyone elsemust show the statement was defamatory, or that it injured her reputation. As a public figure, they must also prove actual malice — in other words, that the reporter knew she wasn't really pregnant, or had "substantial doubt" it was true.

"False statements in the tabloids or elsewhere are not necessarily actionable in court," said Mark Bailen, a media lawyer at Baker Hostelter in Washington.

With her op-ed, Aniston proved what celebrities have always known — sometimes shaming the tabloids is far more effective than a lawsuit, regardless of how much she might want to hurt the tabloids that pick apart every part of her life and body.

"All of that is mean and cruel," Berlik said. "But it's not defamatory."

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