One million people have gained German citizenship since 2000, becoming dual nationals. The data, gleaned by the opposition Greens, follows a Bavarian conservative demand that dual citizenship be abolished.
The Federal Interior Ministry statistics made public Wednesday by the Greens parliamentary group also showed that by 2013 half a million children whose parents were both resident foreigners had acquired German nationality on birth.
Detailed figures showed 958,701 German naturalizations since 2000 and 491,862 newborns of foreign parents recognized initially as German citizens.
Germany's legislature adopted the place-of-birth principle in 2000 after heated electoral debate that saw the then-governing Social Democrats under former Chancellor Gerhard Schröder scuttle their plan to allow full dual citizenship without restraint.
Their modified law change instead required children, once they reach maturity at 18 or before their 23rd birthday, to opt for one of two nationalities, for example, by remaining German but renouncing nationalities derived from their parents.
Last weekend, Bavarian allies of Chancellor Angela Merkel, who have long railed against her liberal refugee policies, demanded in a five-page paper that dual citizenship, even in its limited form, be abolished - in response to recent gains by the anti-mass-migration AfD.
Since 2000, the rate of foreigners seeking German nationalization has slowed to about 110,000 per year - a trend that researchers at the Federal Office for Migration and Refugees (BAMF) attributed in 2011 to "the need to give up one's previous nationality."
Wednesday's figures also recalled that Germany's last census conducted in 2011 had recorded 4.26 million persons who aside from having German nationality also had a further nationality.
The ministry was quoted though as warning that that total had a "large statistical uncertainty" because a subsequent micro-census in 2015 had recorded only 1.69 million dual nationals within Germany.
CDU/CSU 'fantasizing,' say Greens
Greens interior affairs expert Volker Beck claimed Wednesday that in relation to Germany's total population of 82 million, the data debunked anti-migrant sentiment.
"The interior ministers of [Merkel's allied grouping comprising her Christian Democrats (CDU) and the Bavarian Christian Social Union (CSU)] should cease fantasizing about multiple nationalities," Beck told Düsseldorf's "Rheinische Post" newspaper.
It would be more sensible for Germany to "significantly improve" its integration services for immigrants and refugees, said the Greens parliamentarian, whose party accuses Merkel's coalition government of impeding naturalization efforts.
'Modern citizenship law' needed
Early last week, the federal government's integration commissioner, Aydan Özoguz, reiterated her Social Democratic Party's call for Germany to adopt a "modern citizenship law" with the option of dual nationality for all those willing to integrate.
She told the "Frankfurter Allgemeine" newspaper that Germany's naturalization quota lay far below the EU average. Fewer foreign residents were willing to renounce "their old passport."
Berlin election highlights 'gap'
As a result, a gaping hole existed between the population measured in terms of resident foreigners and those Germans with constitutional rights to vote. No society could function in the long term if a large portion was excluded from political participation, she said.
Ahead of Berlin city-state's election next Sunday, the nongovernmental organization Citizens for Europe is campaigning on the issue that more than a half-million Berliners will have no say.
Extra resources for integration
In July, Federal Interior Minister Thomas de Maiziere praised extra funding and higher tutoring wages allocated for integration courses across Germany in the wake of last year's arrival of some one million refugees.
Integration courses introduced in 2005 comprise German language training spread over 600 periods (each of 45 minutes in duration) plus 60 further periods so participants can learn about Germany's legal system, history, politics and culture.
At the end of the course that normally runs over nine months, the participants undergo two tests - on language and knowledge about Germany. Those who qualify receive a certificate that can shorten from eight to seven years their waiting period before acquiring German citizenship.
ipj/kl (dpa, KNA, Reuters)