Franziska Giffey, the Social Democrat party's candidate for mayor of Berlin, resigned as Germany's family minister on Wednesday, saying she wanted to draw a line under plagiarism allegations that have dogged her for three years.
Giffey, once seen as a contender to lead the SPD, said she would now fully devote her energies to her campaign for the Berlin senate elections later this year.
Her resignation is a further blow to the SPD before a federal election in September. Once one of Germany's two main parties, it languishes in third place in most opinion polls, having ceded its place as the leading centre-left party to the Greens.
"In recent days there has been renewed discussion of my 2010 dissertation," she said in a statement. "The government, my party and the public have a right to clarity. I have decided to ask the Chancellor to relieve me of the office of minister."
Berlin's Free University recently concluded a third inquiry into her doctoral dissertation on the European Union and asked Giffey for her comments on the inquiry's so-far unpublished report. Giffey has already said she will no longer use her doctoral title.
"I stick to what I said, that I did my work on the dissertation to the best of my abilities and conscience," she added. "I regret if I made mistakes."
The affair is the latest in a string of plagiarism scandals that have cost top politicians their jobs in a country where a doctoral title is an object of great prestige and held to be useful to a political career.
Karl-Theodor von Guttenberg, a defence minister then seen as a potential successor to Chancellor Angela Merkel, resigned in 2011 after acknowledging copying part of a doctoral dissertation.
(Reporting by Thomas Escritt and Markus Wacket, Editing by Madeline Chambers)
