MADISON, Wis. (AP) -- Gov. Scott Walker has signed a bill that requires schools that teach sex education to stress abstinence as the only reliable way to prevent pregnancy and sexually transmitted diseases.

The Republican bill allows sex ed teachers to ignore contraception completely. Current state law requires schools that choose to teach sex education to use a multi-faceted curriculum that includes contraception use.

Pro-Life Wisconsin and the Wisconsin Catholic Conference back the bill. Opponents say the legislation is foolish and unrealistic.

Walker, a Republican, signed the bill Thursday but announced it Friday.