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ChatGPT creator Sam Altman's sister, Ann Altman, has filed a lawsuit alleging that he regularly sexually abused her between 1997 and 2006.
The lawsuit, which was filed on 6 January in a US District Court in the Eastern District of Missouri, alleges that the abuse started when she was three and Mr Altman was 12.
Mr Altman, who is the chief executive of OpenAI, the firm behind artificial intelligence (AI) software ChatGPT, denied the claims in a joint statement on X with his mother and two brothers.
"All of these claims are utterly untrue," the statement said. "Caring for a family member who faces mental health challenges is incredibly difficult," it added.
Mr Altman said he gives his sister monthly financial support, pays her bills and rent, and offered to buy her a house, but that Annie "continues to demand more money from us".
But Ms Altman claims he "groomed and manipulated" her and performed sex acts on her over several years, including "rape, sexual assault, molestation, sodomy, and battery", according to a court filing seen by the BBC.
Ms Altman said she sustained "great bodily injury", severe emotional distress and depression.
She added that she had incurred numerous medical bills because of medical and mental health treatment for her injuries.
"Over the years, we've tried in many ways to support Annie and help her find stability," Mr Altman said, adding that he had taken "professional advice" on how to "be supportive" without "enabling harmful behaviours".
"This situation causes immense pain to our entire family," the statement added.
The lawsuit added the last instance of the alleged abuse took place when Mr Altman was an adult and she was still a minor.
Ms Altman has previously made similar allegations against her brother on social media platforms such as X.
Billionaire Mr Altman, who married his partner Oliver Mulherin in 2024, is one of the technology world's most high-profile figures.
In late 2022, OpenAI launched the ChatGPT generative AI chatbot. It has become widely used globally for uses as diverse as learning how to flirt, compiling emails, recipes, and assisting students with their homework. It can also write computer code to create websites in a matter of minutes.
In 2024, Mr Altman returned as OpenAI's boss just days after he was fired by the board, surviving an attempt at a boardroom coup.
Additional reporting by Lily Jamali
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