This “alien” skeleton, which has a cone-like skull, was unearthed in the Atacama Desert in Chile around 15 years ago.
Bizarrely, it had 10 pairs of ribs when humans have 12.
Conspiracy theorists went into overdrive following the discovery suggesting the bones were of a monkey or an extra terrestrial that crashed on earth.
But many experts have suggested they belonged to an infant girl who had a range of rare genetic mutations linked to dwarfism.
Scientists suggested she was aged between six and seven-years-old, but latest tests indicate she was less than a four-month-old.
A team from the International Journal of Paleopathology have concluded the skeleton called “Ata” was a 15-week-old foetus and probably the result of a miscarriage.
“This mummy reflects a sad loss for a mother in the Atacama Desert,’ said Dr Bernardo Arriaza, a bioarchaeologist from the University of Tarapacá in Chile.
The new study could explain the floating ribs, which had not developed at this early stage, and the elongated skull which was also not fully formed, reported the Metro.
Previously, a Dr Gay Nolan, who studied the bones, believe they could even help to cure other sufferers because her deformities were so extreme.
He said: “Maybe there's a way to accelerate bone growth in people who need it, people who have bad breaks.
"Nothing like this had been seen before.
“Certainly, nobody had looked into the genetics of it."
According to a Chilean local newspaper, a man called Oscar Munoz found the remain on October 19, 2003 when he was looking for objects of historical value in La Noria, a ghost town in the Atacama Desert.
Near an abandoned church, Munoz found a white cloth containing, according to the newspaper, "a strange skeleton no bigger than 15cm [the size of a pen]".
It was a creature with hard teeth, a bulging head with an additional odd bulge on top.
Its body was scaly and of dark colour.