On Saturday, June 22, Cindy and Kaia wore matching black bikinis on their Florida getaway.
While Cindy, 53, still rocked her curvy look with a white robe draped loosely over her two-piece swimsuit, her girl Kaia, 17, looked skeletal in her bikini.
Kaia revealed her scrawny chest in the brief bikini top. She wore plaid pants over the bottom before stripping all the way down to lie by the hotel pool in her two-piece.
Cindy and husband Rande Gerber's daughter made her runway debut four days after turning 16 and has been busy modeling ever since.
But as RadarOnline.com has reported, Kaia's scary skinny look has stirred concern.
The teen model has insisted she loves to eat.
Cindy hasn't responded to the controversy, but has admitted about the youngster's modeling job, "Kaia had some advantages. She is my daughter, and people know that."
Still, Cindy rejects the idea that nepotism made Kaia famous.
"When people say that I bought her a cover of a magazine, I think, if I was going to buy a cover for someone, it would be me. If I could get someone into a fashion show, I would be getting it for myself," competitive Cindy has said.
The modeling icon added about Kaia, "I couldn't really hold her back. … You hope that all of the advice and guidance and role modeling that you did sticks. That's the stage of parenting when you think, 'Ok, hope you can fly!' "
Scroll through Radar's gallery for more on the mother/daughter dueling bikini bodies!
Fun In The Sun
Cindy and her daughter turned heads in Miami as they headed for the pool.
Kaia looked fragile in her bikini, but she's been seen everywhere looking skinny, even on a recent Starbucks outing with friends in Tribeca.
Cindy and Kaia lounged in deck chairs for their vacay. The younger model was glued to her cell phone during the relaxing day.
Kaia's toothpick frame has led to questions about her overall health.
Exclusive Radar reports shared that while Cindy was trying to keep her daughter away from "the bad girls club," she was actually the one partying with her children! Son Presley, 19, is also a model.
Although Kaia looks like she doesn't eat, her dad Rande revealed on Instagram that the family stuffed themselves at IHOP on Father's Day. "We sat down and ordered every picture on the menu. I love my family!" club owner Rande wrote.
Was Kaia put in the shade? On June 22, Cindy showed off her enviable body at 53. She still does the catwalk at select shows, such as Versace's Spring 2018 tribute to the late designer Gianni Versace. The model and husband Rande often socialize with pals George and Amal Clooney.
Onlookers saw that Kaia's cell phone is decorated with the joke, "Social media seriously harms your mental health." The message included a sexy throwback photo of her mom!
No Meat On Her Bones
Outrageously thin jetsetter Kaia previously looked gaunt in Paris.
Barely There Bling
Kaia sported thin gold necklaces to accessorize her bikini top.
Little Girl Look
Kaia's strappy bikini top exposed her tiny back.
Kaia doesn't seem to care about haters of her shape. She's often flaunted her twig legs in tiny shorts, as Radar has reported.
Junk Food Claim
The young model maintains that she loves to eat, especially chocolate!
Two Peas In A Pod
Cindy and Kaia looked like BFFs during their Miami vacation.
Cindy often stared into space as Kaia kept busy with her social media in their poolside cabana.