With children's early years increasingly recognized as a critical time for learning, more policymakers see a four-year college degree as a necessity for teachers in preschool programs receiving state and federal money. Many state-financed preschool programs require teachers to have four-year degrees. As federal lawmakers debate renewing the Head Start program for disadvantaged preschoolers, they are mulling proposals to move toward a similar requirement for at least a portion of that program's teachers. Yet while those policies reflect what some leading experts in early-childhood education have been advocating in recent years, other researchers say the link between teacher credentials in preschool and outcomes for children is not clear-cut. Indeed, scholars are vigorously debating whether a bachelor's degree should be the standard for teaching in the nation's early-childhood classrooms.