Creates an income tax credit for certain dependents

SB 646 creates a Missouri income tax credit for biological parents of dependents. It provides a $1,000 credit per dependent for married parents (or $1,500 if married before the child's conception), effective for tax years starting January 1, 2026. The credit directly affects married biological parents who qualify for federal dependency exemptions and have state tax liability. Any unused credit amount is refunded, but credits cannot be carried forward or transferred, and the program expires on December 31, 2031, unless renewed by the legislature.