Look carefully.

Click for larger image.
This image arrived unbidden and unannounced at the bottom of an email from the lovely Anna in Berlin. The nativity reconfigured? Naturally, I was intrigued. It took a while, but in a 1993 issue of the Journal of Endocrinology and Metabolism in an article by Maria New & Elizabeth Kitzinger about Pope Joan (a character dear to my heart, but not today) I found an explanation. Philip IV commissioned the painting in 1631( apparently an era of fascination with hermaphroditism) from the great José de Ribera. It is a "portrait of Maddalena de Ventura, the mother of seven, who grew a luxuriant beard at age 37 and is shown nursing her last child when she was 52." The writer goes on to say she she could have suffered from "nonclassical 21-hydroxylase deficiency."
It is good to think about the many permutations in which the nuclear family finds itself.