The Austrian authorities believe enhancing multiculturalism would reduce the risk of jihadism.
But the study, published last year, has bolstered critics of immigration – not least the Freedom Party – in the wake of terror attacks in Berlin, Paris and Brussels perpetrated by Muslims who grew up in Europe.
The Freedom Party is doing well in the polls, as surveys suggest that public attitudes to Muslims have hardened. The ruling coalition has moved to ban full-face Islamic veils in public and to oblige migrants to sign an “integration contract”.
According to its author, Ednan Aslan, a Turkish-born Austrian professor at Vienna University, some 10 000 children aged two to six attend some 150 Muslim preschools, teaching the Quran.
But the first hurdle is that no one knows exactly how many Islamic kindergartens there are. Vienna has 842 registered kindergartens, 100 of them Catholic-run and 13 Protestant, but the number of Muslim ones are not known, as most are privately run.
At least a quarter are funded by Salafist Islamic groups, according to Aslan and they have a clear political objective.
“Parents are sending their kids to establishments that ensure they are in a Muslim setting and learn a few suras (chapters from the Quran),” Aslan told AFP. “But they are unaware that they are shutting them off from a multicultural society,” he said.
The magazine Biber, a minority publication, sent a veiled Muslim reporter undercover posing as a concerned mother looking for a place for her son at 14 Muslim kindergartens.
Even the pro-Islamic magazine found some pre-schools “problematic”, because they were “cutting off or isolating children” from mainstream society. It also voiced concerns about the “openness” of some staff and the level of German spoken.
Vienna City Hall has since sought to calm the debate by commissioning an in-depth study involving a six-strong research team which will be published later this year.
Not only the establishment is worried, but Muslims have also come out against Aslan’s findings. “This study feeds populism and forces Muslims to justify themselves constantly,” said Murat Gurol from newly created pressure group the Muslim Civil Society Network.
Gurol’s own son is in a Muslim kindergarten in order to learn “the values of solidarity, humanity and responsibility”. He told AFP: “I don’t see why that should be allowed for one religion and not for another.”
As the centre of a former vast empire, Austria’s capital is home to 1.8 million people, half of whom have a parent born abroad or who were born abroad themselves.