RALEIGH — Supporters of a proposed constitutional amendment that would ban gay marriage in North Carolina have released their own ad, one day after opponents of the proposal unveiled their ads.

Vote FOR Marriage NC on Tuesday issued a statement saying the ads began running on Monday across the state.

Chairwoman Tami Fitzgerald said in a statement that the ad outlines the importance of preserving marriage, which she said God created as the best environment for having and rearing children.

The Coalition to Protect All NC Families presented its two ads during a news conference on Monday.

The constitutional amendment would define marriage as a union between a man and a woman. Early voting has begun ahead of the May 8 referendum.

Same-sex marriage already is illegal by statute in North Carolina.