Most people would agree that babies are some of the cutest little things on the planet. Their babbling, laughter and wide-eyed enthusiasm can put a smile on just about any face. Another piece of heavy artillery in their arsenal of adorableness is facial expressions.
While it seems like something that would be developed from watching adults, researchers have used 4-D ultrasound technology to discover that they may be developed while still in utero. From 24 to 36 weeks gestation, fetal facial movements become so complex that they can actually be identified as distinct expressions, such as laughing or crying. They can't make the sounds that accompany them, however, until after birth.