Canadian scientists using laser and infrared scans to produce a 3D image of the painting have suggested that the famous smile on Mona Lisa could be because she was pregnant or she just had a baby. Using the laser and infrared scans allowed details beneath layers of paint to be seen – including a gauzy dress then associated with pregnant or new mothers. The researchers said other details obscured by darkened paint and varnish included the hair originally being in a bun and a slightly different posture, as well as the gauze dress. “This type of gauze dress … was typical of the kind worn in early 16th Century Italy by women who were pregnant or who had just given birth,” said Bruno Mottin of the French Museums’ Center for Research and Restoration. The woman herself has been identified as the wife of Florentine businessman Francesco del Giocondo.
Update: Here is a link to infrared photo of Mona Lisa from NY Times.