Laws vary state to state. Jonathan Bates, a family lawyer in Dallas, says that, in most Texas cases, “the parents each have the independent right to consent to noninvasive medical decisions.” But whether vaccination is invasive depends on whom you ask. “Unfortunately, we don’t have a lot of clarity right now,” he says. “It may not be uniform across the state, with as many counties as Texas has.” With that kind of ambiguity, “one parent may go get the child vaccinated, and then it’s done. You can’t put the toothpaste back in the tube,” Bates says.