The case was uncovered in Graz last year and the affected family is now accusing the hospital where the woman was born of incompetence.
The public prosecutor has now ruled that the case can be made public, and an appeal has gone out to 200 women who were born around the same time in the same hospital to take DNA tests to see if they were switched at birth. So far just four women have come forward.
According to a report in the Kleine Zeitung, it's thought that two baby girls were mixed up some time between October 15th and November 20th 1990 at the University Hospital in Graz.
The 25-year-old woman received the shocking news after donating blood. The clinic told her that she had a different blood type than both her parents and therefore could not biologically be their child. A DNA test later confirmed she was not related to them.
Graz University Hospital has defended itself against the allegations of malpractice and said that at present there is no evidence that its staff made any mistake.
“We are making every effort, together with the affected family, to solve this case. If it can be proven that it was our fault, then I want to apologize to all concerned on behalf of the clinic," hospital head Gebhard Falzberger said. He added that it was possible the baby girls could have been swapped after leaving the hospital.
A message on the hospital's website says that it has already carried out an intensive internal investigation, with no results, but that these days the probability of babies being switched at birth in hospitals “is generally very low".
Nowadays babies born in Austria are given two identification wristbands, whereas in the 1990s both mother and baby only had one.
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According to the hospital's records 200 baby girls were born during the same period, and in order to solve the mystery they will all be contacted and asked to take a voluntary DNA test - which they are not legally obliged to do.
The hospital has set up a special task force to deal with the case, and a centre has been set up for women who want to take the free DNA test.
Women who gave birth to a baby girl, or who were themselves born between October 15th and November 20th 1990 in Graz University Hospital can call the team on 0316 385-34567 and make an appointment for a DNA test between 7am and 3pm, Monday to Friday.