"The exercise of conscience, therefore, is a type of rational decision-making. Given that no one else can carry out this task for me (another can offer me moral guidance, but I must accept or reject that advice according to the light of conscience), the Church recognizes that: “Man has the right to act in conscience and in freedom so as personally to make moral decisions.” Quoting Vatican Council II’s document, Dignitatis humanae, the Catechism adds: “‘He must not be forced to act contrary to his conscience. Nor must he be prevented from acting according to his conscience, especially in religious matters.” This would seem to indicate that those who sincerely believe that it would be wrong to vaccinate their children against rubella should be permitted to refuse immunization on the grounds of conscience. One might also appeal here to the priority of the family. The rights of parents in the care and education of their children should take precedence over any duty owed to the state. Under the principle of subsidiarity, decisions about the moral good should be left under the care of those who have the most immediate responsibility and not be usurped by higher authorities. Thus the decisions of the parents have priority over those made by the state."