Image copyright AP Image caption Nan Britton and her daughter Elizabeth Blaesing who was conceived with President Warren Harding

It turns out the rumours were always true - America's 29th president had a love child.

New genetic tests reveal Warren Harding fathered a child with Nan Britton during his presidency.

The tests show that Harding, who was married, was indeed the father of Elizabeth Ann Blaesing, the late Britton's daughter.

Harding's immediate family and the public had rejected the claims and shamed Britton, calling her a liar.

Dr Peter Harding, one of the former president's grand-nephews who spearheaded getting the DNA tests done, told the BBC he is "totally jubilant" to finally know the truth about Blaesing's father.

"This has been a family mystery since I became aware of it," Mr Harding said. "There was no way to really resolve it. Back in the 1920s, there was only whether someone looked like someone else."

He thinks advanced DNA testing was definitely conclusive. Mr Harding and his cousin Abigail Harding pursued the tests with James Blaesing, a grandson of Britton.

'Power of DNA'

Ancestry.com, which provided the test with their AncestryDNA service, confirmed the results were true to the BBC.

"The family connection is definitive," said Stephen Baloglu, an executive at the company.

"It's truly amazing to imagine the power DNA can have in tracing one's family story and in this case rewriting history."

Media playback is unsupported on your device Media caption Alpa Patel of the BBC reports on Harding's "steamy" love letters to another mistress of his, Carrie Phillips

Blaesing died in 2005. Her mother wrote a book, The President's Daughter, in 1927, in an attempt to make money and prove Harding's paternity after his death at 57 as he had left no financial arrangement for their daughter.

"It is totally wonderful to vindicate her. She published her book when women just got the vote and people weren't believing women over powerful men," Mr Harding said. "Look how she survived this thing."

Britton was "vilified by everybody" for claiming President Harding's paternity, including by members of Mr Harding's family, he said, and he is "glad to reverse all that".

Life and death

Image copyright Getty Images Image caption Harding with Florence and father George

born near Marion, Ohio, in 1865

was publisher of a newspaper before entering politics

married divorcee Florence Kling De Wolfe (above)

served in Ohio's state Senate and unsuccessfully ran for governor

elected to US Senate in 1914

won presidential election of 1920 with 60% of popular vote

died in office in 1923 of a heart attack while touring out west

The scandal rocked the 1920s, also known as the "Roaring Twenties" - the president was married and much older than Britton.

"This is a wonderful feminist story, a woman who stuck to her guns and triumphed over 88 years," said Mr Harding.

In the past, the Blaesing family did not want to submit to DNA tests, thinking it insulting to their late matriarch.

Mr Harding hopes to meet more members of the Blaesing family soon and may see them at a family reunion.

"There's a whole lot of children and great-grandchildren of President Harding we've never met. There was something wrong in my whole family mystery I wanted to fix - it left a whole other family out in the cold which was intolerable to me."