ST. LOUIS — Missouri healthcare advocate Leslie Ortbals and her husband want to start a family, but she worries they can’t afford it. The 27-year-old said she takes 10 medications daily to manage multiple chronic illnesses. Now she worries the cost of those drugs could rise — not because of price increases, but because of a tax system revamp put on the ballot by the state’s Republican-dominated legislature and backed by the Republican governor. Prescription drugs and doctor visits are currently exempt from taxes in the state. But in August, Missouri voters will weigh in on a proposed con...