STUCK: A measles epidemic called attention to permissive waiver rules. (Robyn Beck / AFP / Getty Images)

As a nationwide measles outbreak grows, state legislatures are pushing through bills that would make it harder for parents to opt out of vaccinating their children.

On Feb. 4, legislators in California, where a measles outbreak at Disneyland last month drew national attention, introduced legislation that would eliminate vaccination waivers except for medical reasons, such as weakened immune systems. Bills pending in that state and in at least two other states come as parents with increasing fears about their children’s exposure to measles and other diseases have few legal options to combat the growing numbers of those who choose not to vaccinate.