Which reflex involves the baby's toes fanning out when the foot sole is stroked?

The Babinski reflex is a normal reflex observed in infants, characterized by the fanning out of the toes when the sole of the foot is stroked. This reflex is considered part of the neurological development in young children and is typically present in infants up to about 2 years of age. The presence of this reflex can indicate proper functioning of the nervous system. As the child grows older, the reflex typically disappears as the nervous system matures.

This reflex indicates that the pathways in the brain and spinal cord related to movement and coordination are functioning as expected. A positive Babinski reflex usually means that the infant's central nervous system is responding correctly, which is an important aspect of developmental milestones.

In contrast, the other options describe different reflexes that are unrelated to toe fanning: the laughing reflex pertains to emotional responses, the grasping reflex involves the baby's fingers closing around an object, and the Moro reflex is a startle response that occurs when a baby feels like it is falling or hears a loud sound. Each of these reflexes serves distinct purposes in early development, but they do not involve the fanning of toes as seen in the Babinski reflex.