At its heartwarming core, Christmas is the story of a birth: the tender relationship between a new mother and her newborn child.

Indeed, that maternal bond between the Virgin Mary and the baby Jesus has resonated so deeply across the centuries that depicting the blessed intimacy of the first Noel has become an integral part of the Christmas industry.

Yet all the familiar scenes associated with the holy family today — creches and church pageants, postage stamps and holiday cards — are also missing an obvious element of the mother-child connection that modern Christians are apparently happy to do without: a breast-feeding infant.

Jesus certainly wasn’t a bottle baby. So what happened to Mary’s breasts? It’s a centuries-old story, but one that has a relatively brief answer: namely, the rise of the printing press in 15th-century Europe.

With the advent of movable type, historians say, came the ability to mass-market pornography, which promoted the sexualization of women’s bodies in the popular imagination. What’s more, the printing press enabled the wider circulation of anatomical drawings for medical purposes, which in turn contributed to the demystification of the body. Both undermined traditional views of the body as a reflection of the divine...

...The cultural shift was so great that even Catholics soon came to regard the breast as an “inappropriate” image for churches. Instead, the sacrifice of the cross — the suffering Jesus — became the dominant motif of Christianity while the Nativity was sanitized into a Hallmark card.

“Ask anybody in the street what’s the primary Christian symbol and they would say the crucifixion,” said Margaret Miles, author of “A Complex Delight: The Secularization of the Breast, 1350-1750,” a book that traces the disappearance of the image of the breast-feeding Mary after the Renaissance.

“It was the takeover of the crucifixion as the major symbol of God’s love for humanity” that supplanted the breast-feeding icon, she said. And that was a decisive shift from the earliest days of Christianity when “the virgin’s nursing breast, the lactating virgin, was the primary symbol of God’s love for humanity.”

In fact, the oldest known image of the Virgin Mary is from a third-century fresco in a Roman catacomb that shows the infant Jesus suckling at her exposed breast.

[See photo above right of the fresco in the Catacomb of Priscilla on the Via Salaria in Rome, Italy.]