MADISON, Wis. -- Schools that decide to teach sex education would have to instruct students on the use of birth control under a bill up for debate on Tuesday in the state Assembly.

The measure is being opposed by anti-abortion groups and the Wisconsin Catholic Conference.

Under the measure, if schools opt to teach sexual education, they would be required to address the health benefits, side effects and proper use of contraceptives and other methods to prevent pregnancy and sexually transmitted diseases.

Parents could view the instructional materials and chose to not have their child participate in class.

Supporters of the new requirement include Planned Parenthood, groups representing nurses and health departments, and the state teachers' union.