Democratic Gov. Steve Bullock is strategically allowing an abortion measure to become law without his signature so that it can be challenged in court.

House Bill 391 would require minors to obtain parental consent before getting an abortion.

Bullock said the bill violates Montana's constitutional guarantees to equal protection and privacy in a statement released Thursday. Bullock developed the strategy with women's health advocacy groups who plan on challenging the new law.

Planned Parenthood of Montana said it would file a lawsuit challenging the law's constitutionality.

It's nearly identical to a referendum measure that passed both chambers and was scheduled to appear on the ballot in 2014.

The referendum dies with the bill becoming law.