Paris Hilton's mother is proud of her daughter's homemade sex tape, according to a new biography. Biographer Jerry Oppenheimer claims that while researching his book 'House of Hilton' he found that 25-year-old Paris' parents, Rick and Kathy, were not fazed when 'One Night In Paris' was leaked onto the internet, and eventually released as a DVD, without her permission. He is quoted by the New York Daily News newspaper as saying: "I have family sources telling me that Rick and Kathy Hilton are proud of everything Paris has done, including the X-rated video that launched her to this international stardom, infamy and fame."It is a bizarre family. Behind the scenes her parents were not opposed to the video because that totally launched her."The author also says he ended up feeling sorry for 'The Simple Life' star because her mother pressurised her to become a celebrity. Oppenheimer added: "Her mother, Kathy, put her in make-up and allowed her into nightclubs from a very young age."I feel sorry for her because in a way she had no chance to do anything else but live the dreams her grandmother and her mother had for themselves."My goal in doing this book was to figure out how she became who she is."I came away from this research with a lot of sympathy for Paris. I came away feeling a bit sympathetic for her because I don't think she had a chance to do anything besides what she is doing. "The accredited biographer also claims that Paris - who has marketed herself as a brand, earning millions from her own reality TV show, perfume, pop album and acting career - will not inherit the large portion of the Hilton hotel fortune people assume she will. Oppenheimer said: "While in name she is a Hilton, she is not the heiress the world has been led to believe. In fact she has to work her tush off to live the Hilton lifestyle. The bulk of the Hilton fortune is going into the Hilton Foundation. Paris is one of many grandchildren and great-grandchildren who have to work for a living."Her brilliance is getting the attention - the exhibitionism, canoodling with guys in clubs and getting on the covers of celebrity magazines around the world."