New scientific tests suggest a fragment of papyrus in which Jesus speaks of "my wife" is more likely an ancient document than a forgery, a Harvard professor has said.

The text, written in Coptic and about the size of a business card, specifically contains the phrase "Jesus said to them, my wife", according to an article published by the Harvard Theological Review.

Professor of divinity Karen King says the papyrus probably dates to eighth-century Egypt, based on radiocarbon dating and tests on the ink's chemical composition.

"If it was written in the eighth or even the ninth century, it's still an ancient document," she said. "It's not a modern forgery."

But, she stressed, the fragment ddi not prove that the historical Jesus was actually married. Most reliable evidence from early Christianity is silent on Jesus' marital status.

If anything, she said, the papyrus provided insight into early Christianity's debates over family life.

"Early Christians were extremely interested in whether or not they should marry or be celibate or whether it was OK to have a family or whether one should remain virginal," Prof King said.

She said the papyrus, which contains about eight partial lines of text, appears to make the case that mothers and wives can be disciples. Jesus references his mother, wife, and another female as his disciples apparently discuss whether a woman - identified as "Mary" - can join their ranks.

According to Prof King's translation, the text then reads "Jesus said to them, "My wife ...". That is followed in the next line by "... she is able to be my disciple ...".

Prof King originally revealed existence of the papyrus in 2012. Calling it the "Gospel of Jesus's Wife", her announcement sparked debate among religious and ancient scholars. But publication of her findings was delayed for the tests. She maintains the "gospel" moniker was appropriate.

While the papyrus is too small to discern anything definitive about who composed it, Prof King argued that the text belongs to a body of ancient texts that illuminate facets of Jesus' life. "It contains a dialogue between Jesus and his disciples," she said. "That would normally put it in the category of gospel."

Prof King hopes the research puts to rest questions about the text's authenticity.

But Brown University professor Leo Depuydt, in an analysis also published by the Harvard Theological Review, was not convinced. He said the text contained grammatical errors that a native Coptic speaker would not make. Prof King suggested that the text was written in an informal style found in other ancient Coptic texts.

Others have questioned the mysterious provenance of the papyrus.

Prof King says she obtained the text in 2011 from a donor that wants to remain anonymous. That owner had bought the text in 1999 from a collector who, in turn, had acquired it in East Germany in about 1963.