Lady Colin Campbell, 62, made the claim at the official launch in London of her new biography of the Queen Mother.
In The Queen Mother, The untold story of Elizabeth Bowes Lyon, who became Queen Elizabeth the Queen Mother she also said the Queen’s late sister, Princess Margaret, was not conceived naturally because their mother “preferred not to partake in certain aspects of marital life”.
The primary source for the information, she claims, had been the Duke of Windsor – the Queen Mother’s brother-in-law.
He was involved in a bitter dispute with her during the Abdication Crisis – with the latter claiming the heir to the throne’s partner, Wallis Simpson, held sway over his judgment because of sexual techniques she learned working in a bordello in China.
Lady Campbell, referring to the Queen’s parents, said: “They needed children and they got children. Their two girls were their mother’s and father’s progeny, they were simply conceived by artificial inception. Elizabeth didn’t do sex.”
Lady Campbell also claimed the Queen Mother was actually the daughter of her family’s French cook, an “early version of surrogacy” which was common in aristocratic circles.
That information is also said to have come from the Duke of Windsor, who went on to spread the nickname “Cookie” for the Queen Mother.
The author said the cook – an “attractive and pleasant Frenchwoman” called Marguerite Rodiere – gave birth to the future Queen Mother because Cecilia Bowes-Lyon, who already had eight children, was advised not to have any more.
Lady Campbell said: “The book is, hopefully, a very fair and accurate portrait of a human being.
“Queen Elizabeth, the Queen Mother, I know has been regarded as a fantasy figure. But she was not a fantasy figure, she was a human being and a very complex, interesting, dynamic and charismatic human being of great ambition and great resourcefulness.
“She is a far more interesting character than she has hitherto been portrayed as being. I have used royal diaries and letters from the Royal archives to pin things down.”
Saying the Queen Mother has been portrayed as a “marshmallow made of steel”, Lady Campbell added: “The steeliness has never come out so far; the tremendous influence she had politically and the tremendous influence she had upon our lives in the western world because of her political astuteness. It has just been this adorable granny.”
Admitting she knew her revelations would shock people, she said: “There is no point in writing a biography unless you upset everybody.”
She later added: “I do not think there is much in this book that is unknown since much of it came from the various members of the Royal family. Inconvenient, yes, uncomfortable, yes, shockwaves, I do not think so.”
She said the Queen Mother’s father, Lord Glamis, had confided in his doctor and “on his death bed, confirmed it was absolutely true”.
Last night a spokesman for Buckingham Palace said they did not wish to comment.
• Lady Colin Campbell has been a controversial figure in aristocratic circles since her marriage to Colin Campbell, younger brother of the 12th Duke of Argyll.
She was born to a wealthy, upper-class family in Jamaica, but a genital deformity meant she was raised as boy until her late teens. She worked as a model in New York and in her late 20s had gender realignment surgery.
She became engaged to Colin Campbell in 1974 the night they met and married within a week. The marriage ended after 14 months amid allegations of violence and accusations that he sold details of her medical background to the media.
She has written a number of books including Diana in Private and The Royal Marriage.