A torn condom given to Swedish police by one of the alleged victims was examined by staff at two forensic laboratories but they could not find any conclusive evidence of Mr Assange’s DNA on it.
The same forensic teams found DNA thought to belong to the WikiLeaks boss on another condom, which was submitted by the second alleged victim.
The revelation is contained in a 100-page police report that was written after witnesses were interviewed and forensic evidence had been examined.
The report, which has been seen by Mr Assange’s lawyers, has led to the Swedish authorities requesting his extradition from Britain to stand trial, though he is yet to be charged with any offence.
Mr Assange, who denies allegations of rape and sexual molestation, has been fighting extradition to Sweden for the past two years. He claims it is a ruse to send him to the United States where he could face trial for espionage.
The 41-year-old is currently holed up in the Ecuadorian Embassy in London after being granted asylum by the country’s president, Rafael Correa.
In the report, the first alleged victim, now 33, claims she was sexually molested by Mr Assange at her flat in Stockholm on several occasions.
She also claims that Mr Assange deliberately ripped a condom before wearing it so that he could have unprotected sex with her against her will.