A reader writes:
Dish readers might also enjoy, in English, the great art historian Leo Steinberg's major (definitive?) 1983/1996 study on the subject: The Sexuality of Christ in Renaissance Art and in Modern Oblivion. From the publisher's gloss:
Steinberg's evidence resides in the imagery of the overtly sexed Christ, in Infancy and again after death. Steinberg argues that the artists regarded the deliberate exposure of Christ's genitalia as an affirmation of kinship with the human condition. Christ's lifelong virginity, understood as potency under check, and the first offer of blood in the circumcision, both required acknowledgment of the genital organ. More than exercises in realism, these unabashed images underscore the crucial theological import of the Incarnation.
Money quote from the book:
"The longer one dwells on the theological grounds for genital shame, the more imperative that Christ be therefrom exempted."