In the permanent collection of the National Gallery in London’s Trafalgar Square, a painting by Peter Paul Rubens illustrates the dilemma facing art administrators as they attempt to achieve gender — and genital — balance in the display of male and female nudes.

The Judgment of Paris portrays three naked goddesses, two of them full frontal, and three male gods, also naked but more decorously posed. The buttock and nipple counts are equal but only the women bare their genitals. What kind of balance is that?

Last week’s announcement that the Royal Academy (RA) is aiming for equal exposure of naked men and women next March in an important exhibition of Renaissance nudes has sent a tremor through the international art world. Read more