The 'excruciating anguish' of John Edwards' wife as she faced her husband's affair - and terminal cancer

Mr Edwards has admitted having an affair with Rielle Hunter in 2006, but denies that he fathered her five-month-old child.

He offered to undergo a DNA test to prove this.

Affair: Rielle Hunter who had an affair with former US Democratic presidential candidate John Edwards has said she will not participate in DNA testing to see if her five-month-old daughter is his

But Miss Hunter's lawyer, Robert Gordon, said on Saturday that his client is a private individual who wishes to maintain her privacy and therefore she will not take the test.

This means her daughter's paternity is still in doubt.

Hunter's daughter, Frances Quinn Hunter, was born on February 27 this year, and no father's name is given on the birth certificate filed in California.

A former Edwards campaign staff member is said to be the father.

Edwards, a former North Carolina senator who was the Democratic vice presidential nominee in 2004, confessed to ABC News that he had lied repeatedly about the affair with Hunter, then 42, who produced videos for Edwards as he prepared to launch his presidential campaign.

In an interview which aired on ABC's 'Nightline' on Friday night, Edwards said he would be willing to take a paternity test to put the issue to rest but was not sure whether Hunter would be willing to.

'I am and have been willing to take any test necessary to establish the fact that I am not the father of any baby, and I am truly hopeful that a test will be done so this fact can be definitively established,' Edwards said.

The National Enquirer first reported on the affair in October 2007, in the run-up to the Democratic primaries, and Edwards denied it.

United: John Edwards and his wife Elizabeth who campaigned with him while he was running for presidential candidacy

Last month, the Enquirer carried another story - the headline referred to an Edwards 'love child' - stating that its reporters had accosted Edwards at the Beverly Hilton Hotel in Los Angeles where he had met with Hunter after her child's birth.

Edwards called it 'tabloid trash.'

In a statement on Friday, Elizabeth Edwards said it was not easy to find out about the extramarital affair in 2006 but indicated she did not believe that her husband was the father of Hunter's daughter.

'This was our private matter, and I frankly wanted it to be private because as painful as it was I did not want to have to play it out on a public stage as well,' she said.

'Because of a recent string of hurtful and absurd lies in a tabloid publication, because of a picture falsely suggesting that John was spending time with a child it wrongly alleged he had fathered outside our marriage, our private matter could no longer be wholly private.'

Edwards declared his presidential candidacy in December 2006.

His wife campaigned enthusiastically with him and by herself in the months that followed.

Campaign trail: John Edwards stands with his family after a post-caucus rally in Des Moines, Iowa

She announced in March 2007 that her cancer, formerly in remission, had returned and there apparently was no cure.

Edwards dropped out midway through this year's primaries. He recently endorsed Barack Obama and had been mentioned as a possible running mate.

But as rumours spread of Edwards' possible affair it became clear that he was unlikely to speak at the Democratic National Convention later this month in Denver.