A 20 year old Californian woman, Mariah Yeater claims Justin Bieber is the father of her 3-month-old baby son. She is saying that Justin Bieber is the father of her baby boy. The Canadian teen pop sensation Justin Bieber is reportedly facing a paternity lawsuit in California that accuses him of impregnating a fan after a brief sexual encounter backstage.

The 17-year-old singer's representatives are calling the allegation "malicious, defamatory and demonstrably false," saying "While we haven't yet seen the lawsuit, it's sad that someone would fabricate malicious, defamatory, and demonstrably false claims”.

Mariah Yeater claims she was 19 years old when she had sex with Justin Bieber backstage at one of his Los Angeles shows last year. She alleges, he told her the tryst was his "first time." Radar Online quoted from Yeater's affidavit, which was not available online, where she claims to have asked Bieber to put on a condom, but the singer did not.

In the lawsuit, Yeater, who was 19 at the time, alleges that a security guard asked her if she wanted to meet the singer after a concert at the Staples Center in Los Angeles, California, on Oct. 25, 2010.

Mariah Yeater is demanding Justin Bieber to take a paternity test “to scientifically confirm” he is the father of the child. The papers were filed in late October and Yeater asks the court for Bieber to provide adequate support for her baby.

The allegations have not been proven in court, and Bieber's representative strenuously denied them.

Beiber’s camp told E! News in a statement, “We will vigorously pursue all available legal remedies to defend and protect Justin against these allegations."