A controversial measure was signed into effect by Gov. Jerry Brown today.

The law requires children who enter school or daycare to be vaccinated against diseases, regardless of religious or personal beliefs. The only exception would be for children with medical conditions such as allergies or immune-system deficiencies that have been confirmed by a physician. It is one of the nation’s toughest mandatory childhood vaccination bills. But Brown says the benefits outweigh the risks.

Parents can get around the vaccination law by enrolling their children in private, home-based schools or doing independent studies off campus.

Parents in opposition to the bill believe it violates their parental rights to protect their children’s health and the right to a public education.