Mexican officials confirmed that the girl, known only as Dafne, was older than her mother originally said when she spoke to police, the Daily Mail reported. Officials said they conducted an 'anthropological review,' to determine her age, but did not give further details.
DNA tests confirm that the baby's father is in fact Dafne's 44-year-old stepfather, not her 17-year-old boyfriend.
According to Jalisco State Prosecutor's Office spokesman Lino Gonzalez Corona, the stepfather is under arrest after admitting having at least two sexual encounters with Dafne--one in April and another in June, ABC News reported.
Dafne's birth certificate, which says she was born in October 2003, was issued in November 2011 by the municipality of Ixtlahuacan de Los Membrillos, where Dafne's family had been for six years. Her family reportedly obtained the document after they were told she would need it to go to school.
The birth certificate also lists the stepfather as the father.
Jose Ramirez, a spokesman for the prosecutor's office, said the stepfather's male relatives were also undergoing DNA testing to eliminate the possibility one of them is the father.
Jalisco district president Dr. Sergio Ramon Quintero Gonzalez said the investigation has not turned up any evidence the 17-year-old boyfriend--originally named as the father--even exists.
"Dafne's mother said that the boyfriend is from the neighborhood but nobody has heard of him," he told the Daily Mail. "We have no name and nobody knew he was her boyfriend."
If convicted, the stepfather could face 10-12 years in prison.