Dominic is left-handed. He would like to know if his infant son is likely to be left-handed or right-handed. What can you tell him about research on handedness?

What will be an ideal response?

Answer: Handedness reflects the greater capacity of one side of the brain—the individual's dominant cerebral hemisphere—to carry out skilled motor action. Research on handedness supports the joint contribution of nature and nurture to brain lateralization. Left-handed parents show only a weak tendency to have left-handed children. One genetic theory proposes that most children inherit a gene that biases them for right-handedness and a left-dominant cerebral hemisphere. But that bias is not strong enough to overcome experiences that might sway children toward a left-hand preference. Even prenatal events may profoundly affect handedness. The orientation of most singleton fetuses—facing toward the left—is believed to promote greater control over movements on the body's right side. Handedness also involves practice. Newborns' bias in head position causes them to spend more time looking at and using one hand, which contributes to greater skillfulness of that hand.