Final answer:
In adults, the presence of the Babinski reflex, indicated by the extension and splaying of the toes upon stimulation of the foot sole, suggests a neurological problem and can impair walking and balance.
Step-by-step explanation:
For an adult, the Babinski reflex should not be present. The Babinski reflex is characterized by dorsiflexion of the foot with extension and splaying of the toes when the sole of the foot is stimulated. This is a typical response in newborns as part of their developmental reflexes. As a person matures, this reflex is typically inhibited by the input from the corticospinal tract. The absence of this reflex inhibition in adults is indicative of a neurological problem, such as reduced myelination of the spinal tract or an upper motor neuron lesion. In adults, a positive Babinski sign potentially compromises walking and balance due to inappropriate extension of the foot and splaying of the toes in response to the plantar reflex, which is typically employed for maintaining balance and coordinating movements.