A girl born in Peru with fused legs could be walking within two years after a successful operation to separate the limbs, her doctors say.
Doctors said circulation was good in both feet
Luis Rubio, who heads Milagros Cerron's medical team, said the one-year-old was now able to wriggle her legs and was responding well to medication.
But Milagros, dubbed "little mermaid" because of the defect, will still need many more operations, he said.
Correspondents say Wednesday's procedure exceeded expectations.
Surgeons were able to separate Milagros' legs further than planned - to above the knees.
Babies with her condition - sirenomelia - usually die within days of birth as their internal organs are also badly affected.
The little girl's fate has been followed closely by Peruvians.
'Nothing could be fatal'
Dr Rubio began operating on the girl at 2230 local time on Tuesday evening (0330 GMT on Wednesday) in a hospital in Lima.
Milagros celebrated her first birthday a month ago
The team, including trauma surgeons, plastic surgeons, cardiovascular surgeons, neurologists, gynaecologists and a paediatrician, spent four-and-a-half hours on the procedure.
Dr Rubio gave a running commentary to journalists during the operation.
He said early indications after the procedure were good.
"Fifteen hours after surgery ended... her vital signs are stable and she's awake," he said.
"Her spirits are very high, her crying is energetic, her breathing is good and there is nothing now that could be fatal."
He added that there was "extraordinary" capillary flow and reflexes on each foot were working independently.
"In accordance with the anatomic findings that we have encountered, it is possible that she will walk," he said.
But the doctor said another operation would be necessary in five or six months to further separate her limbs up to her pelvis.
She will also need operations to reconstruct sexual, digestive and other internal organs, along with her splayed feet, at a later date.
Most sirenomelia sufferers have severe organ damage and die within hours.
The only person who is known to have survived in the long term is 16-year-old American Tiffany Yorks, whose legs were separated before she was one year old.
Milagros was born in the mountain city of Huancayo, 200km (125 miles) east of Lima - Peru's capital - to a very poor family.
However, the costs of the operation are being met by the city of Lima, whose mayor is the girl's godfather.
STAGES OF SEPARATION PROCEDURE
1 - Legs are fused together by skin and feet splayed in a V-shape
2 - Saline sacks inserted and gradually filled to stretch the skin
3 - Legs separated, using the stretched skin to cover the wounds
4 - A later operation will rotate splayed feet forward