The sex secrets of the young Barack Obama have been revealed in an authoritative new biography of the ex-president.

Obama slept with his girlfriend Genevieve Cook on their first date, before she wrote him a poem about their ‘f***ing’ and called their sex ‘passionate’, the book about the former president reveals.

They also did cocaine together – and after they split she slept with his best friend.

Obama also considered a gay relationship while at college, twice proposed to another white girlfriend, and cheated on Michelle with his ex during the first year of their relationship.

His past is revealed in the 1,078-page biography Rising Star: The Making of Barack Obama, to be published on May 9.

Obama, a new Columbia graduate who was working for a firm that  prepared financial reports at the time, made dinner for Cook at his apartment in Manhattan two weeks after meeting her at a New Year’s Eve party and handing her his phone number.

It was the start of a relationship which is one of a series revealed in Rising Star.

The 1,078-page biography is the most comprehensive work ever on Obama and the first to be published since he left office.

It was written after exhaustive research by Pulitzer-prize winning biographer David Garrow, and also reveals how he asked another woman to marry him – and continued a relationship with her while dating Michelle, before she became his wife.

Cook was 25 when she met 22-year-old Obama on New Year’s Eve in 1983.

Australian-born Cook was living in her mother and stepfather’s Park Avenue apartment at the time, but had been brought up around the world, including – like Obama, Indonesia – as her father was an Australian spy and diplomat.

She wrote about it in a private memoir and said that at the party ‘I remember being very engaged and just talking nonstop’ with Obama.