Sam Altman has denied claims made by his sister in a new lawsuit that he sexually abused her as a child. 

The 39-year-old OpenAI CEO is the co-founder of the San Francisco-based company behind ChatGPT and a venture capitalist, who Forbes says amassed much of his $1 billion through investments. 

Ann Altman, 30, filed a complaint Monday in a US District Court in Missouri - where the siblings grew up - that alleged her brother molested her between the years of 1997 - when Ann was just three years old and Sam was 12 - and 2006. 

The disturbing lawsuit, which names Ann Altman as the plaintiff, says that Sam 'groomed and manipulated [her] into believing the aforementioned sexual acts were her idea, despite the fact she was under the age of five years old when the sexual abuse began and [she] was nearly a teenager.'

It claimed that Sam Altman 'forced [her] to touch his penis and perform oral penetration on him.'

Ann Altman claimed that because of this alleged abuse, which would happen 'several times a week,' she 'suffered a loss of enjoyment of a normal life as a consequence of her emotional injuries.'

She is seeking $75,000 in legal fees and unspecified damages from a jury trial, per the complaint.

Sam Altman - who came out as gay to his parents at the age of 16 - posted a statement to social media Tuesday credited not just to himself but his mother Connie and brothers Max and Jack denying the allegations.

'Annie has made deeply hurtful and entirely untrue claims about our family, and especially Sam. We've chosen not to respond publicly, out of respect for her privacy and our own. However, she has now taken legal action against Sam, and we feel we have no choice but to address this,' they wrote.

They added that Annie 'faces mental health challenges' and they have helped her financially - including promising to buy her a home and pay her rent and medical expenses - but said she 'continues to demand more money from us.'

Ann has, according to Sam, his brothers, and mother, made increasingly extreme allegations against her family over the years, leading up to this lawsuit.

Those allegations included withholding her share of their late father Jerry's 401k funds, hacking her WiFi and shadowbanning her from various social media outlets.