A Peruvian baby dubbed the “Little Mermaid” because she was born with a rare condition in which her legs are fused, will have surgery this month to try to separate them, doctors said.

Nine-month-old Milagros Cerron - her name means miracles in Spanish - is one of only a handful of the estimated 1-in-60,000 to 100,000 people born with sirenomelia, or mermaid syndrome, to have lived more than a few hours, experts say.

For Luis Rubio, the doctor leading the Peruvian team that will cut her legs apart in Lima on February 24, the past year has been a crash course in tackling a condition he had read about in textbooks but never expected to treat.

Doctors believe there may only be one other surviving “mermaid,” 16-year-old American Tiffany Yorks, whose legs were separated when she was a few months old.

Experts say sirenomelia is about as rare as conjoined twins but is nearly always fatal because most sufferers lack kidneys or have other complications.

“It is very, very rare,” said Prof. Pierpaolo Mastroiacovo, director of the Rome-based International Center of Birth Defects. “The presence of renal agenesis (absence or imperfect development) makes survival very rare and improbable.”

From the waist up, Milagros smiles and babbles like any healthy infant. Below the waist, her stomach merges seamlessly into her legs, which are joined all the way to her heels.

With her tiny feet splayed in a ‘V’, the impression of a mermaid’s forked tail is complete.

The bones of both legs are visible and move separately, “as if she wanted to get free of this sack,” Rubio said.

He took on Milagros’ case when she was two days old and is treating her in a City Hall-funded mobile “solidarity hospital” run out of old buses in a poor northern district of Lima.

‘TOTAL DESPAIR’

Milagros’ father, Ricardo Cerron, 24, appealed for aid when she was born on April 27, 2004, in the Andean town of Huancayo, around 200 miles (300 km) east of Lima.

“I thought it was something horrifying” he said, recalling his reaction on seeing his daughter. “I was in total despair.”

Her legs have separate cartilage, bones and blood supplies, and she has one good kidney. Her heart and lungs are fine.

Milagros, who weighs 17 lbs (7.5 kg) and is 24 inches (60 cm) long, has a rudimentary anus, urethra and genitalia all located together.

Doctors will insert three silicone bags filled with saline solution between her legs on February 9 and gradually add liquid to stretch the skin to cover exposed wounds once they are cut apart, centimeter by centimeter.

“I have faith it will all go well,” said Milagros’ mother, Sara Arauco, 19.

But Mutaz Habal, the doctor who began treating Tiffany Yorks when she was one hour old and helped pioneer the separation technique, said it was hugely risky.

“My only desire is to have another survivor,” he told Reuters. He said he did not know of any besides Tiffany.

Tiffany, who lives in New Port Richey, Florida, walked for six years after her separation surgery but is currently wheelchair-bound after an accident. “I have the highest hopes that (Milagros) is going to go on for a long time,” she said.

“We want to dream that she could one day run or ride a bike,” Rubio said. “But if we could just give her the ability to be independent, that’s enough.”