A male flight attendant learned firsthand why you should never, ever ask a woman if she's pregnant (unless you're 100 percent sure!).

By baby teeth chart
October 28, 2015
Grethe Andersen
Credit: Stuff.co.nz on YouTube

It's a well-known fact that you never, EVER ask a woman if she's pregnant. Even if she looks like she has a beach ball under her shirt. Even if she's stroking her bump and talking about ultrasounds. Even if she's on her way to the delivery room. Just don't.

This advice would have served one Jetstar Airlines employee well this past weekend. It all began when 24-year-old Grethe Andersen was hopping on a Jetstar flight to Auckland, New Zealand, with some of her friends. The employee, a male flight attendant, dropped his gaze to Andersen's midsection and asked her how far along she was. The question took her aback—at first, she thought he was asking how heavy her bags were—but she quickly recovered and said she wasn't expecting.

As Andersen later found out from the crew leader, Jetstar has a policy requiring women more than 28 weeks along to carry a signed certificate from their OB confirming info like the due date and whether there have been any complications with the pregnancy. Exactly how they determine the difference between a food baby and a real baby remains a mystery.

This isn't the first time the airline has ignored society's don't-ask policy. Back in 2012, it reportedly pulled the same thing on a 21-year-old who wasn't pregnant and also kicked two moms-to-be off their flights because they were 35 and 32 weeks along, respectively. (Doctors in the U.S. recommend pregnant women stop flying after 36 weeks.)

Andersen, naturally, was pretty upset with Jetstar. She vented on the company's Facebook page, writing that she "was there to celebrate with my girlfriends, dress up and look good. As a woman, it's not a good feeling when you're asked if you're pregnant and you're not." In response, some mamas shared bump photos proving that Andersen's tiny stomach looks nothing like a preggo's belly.

As a way of making amends, Jetstar gave an overdue apology and a voucher for a paltry $NZ100 (or $67). Not surprisingly, it wasn't quite enough for Andersen. She told the Sydney Morning Herald that what the airline should do is school its employees in how to broach the pregnancy question. "It is a tough subject to approach, but it can be done way differently," she says. Of course, it also helps if you have a killer comeback.

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Bonnie Gibbs Vengrow is a New York City-based writer and editor who traded in her Blackberry and Metro card for playdates and PB&J sandwiches—and the once-in-a-lifetime chance to watch her feisty, funny son grow up. Follow her on Twitter, Pinterest, and Google+.