LANSING, Mich. (AP) — Supporters of amending Michigan’s constitution to prohibit discrimination based on sexual orientation and gender identity have cleared an initial procedural step.

The Fair Michigan ballot committee’s petition form was approved Tuesday by the Board of State Canvassers. The group now must gather roughly 315,000 valid voter signatures by the summer to put the measure on the November 2016 statewide ballot.

The state constitution bars discrimination because of religion, race, color or national origin. The amendment would add gender, gender identity, sex and sexual orientation protections.

The Republican-controlled Legislature has blocked bills to protect gay and transgender residents by updating Michigan’s civil rights law. Gay rights advocates are divided over whether a ballot proposal should be initiated, however, with some worried it would be defeated.