MOVE over Da Vinci, here comes Mary Magdalene. In the latest twist to the seemingly endless literary debate over the roots of Christianity, a controversy is looming over a novel by an author who claims to be descended from Jesus Christ.

It may sound familiar to readers of Dan Brown’s blockbuster The Da Vinci Code, but Kathleen McGowan, an American who began her career as a journalist in Belfast, has persuaded publishers that her claims that Magdalene married Jesus and bore his children should be taken seriously.

“I don’t want people to think I’m claiming to be some elitist figure in the [Jesus] bloodline,” said McGowan, who has pocketed a seven-figure advance for her novel, The Expected One. “But what I’m saying is that Mary and Jesus had children and after 2,000 years of procreation there are probably millions of descendants around the world. I believe I’m one.”

The book will be published in New York on Tuesday. It has earned $2m from the sale of foreign rights and will appear in Britain on August 7.

McGowan, 43, said she had submitted her proposal to publishers in 1997, six years before Brown published The Da Vinci Code. “I was laughed out of New York city,” she said last week as she toured Languedoc, in southwest France, where she is at work on a sequel. “I was told nobody would ever publish a book claiming Jesus was married to Mary Magdalene.”

She published the book herself last year after selling shoes on eBay to pay for research. It sold only 2,500 copies but was snapped up by Touchstone Books, an imprint of Simon & Schuster.

The Expected One tells the story of Maureen Paschal, a journalist searching in the Pyrenees for scrolls supposedly written in the 1st century by Magdalene.

Scepticism has been fuelled by McGowan’s reluctance to publish evidence of her claim to be descended from Jesus. Asked to produce ancient family documents that she claims to have uncovered in France, she said she had been “asked not to talk about what I’ve seen. I know it sounds very cloak and dagger, but here in the Languedoc I’ve been followed, and that world is very much alive down here”.

Trish Todd, editor-in-chief of Touchstone Books, believes the claims. “Her passion and her mission are so strong,” she said.

Others are sceptical. “There is no historical evidence that would suggest that Jesus and Mary had any children [who] grew up in France and then moved throughout Europe,” said Marvin Meyer, a professor of bible and Christian studies in Orange, California.

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