A Colorado proposal to require marijuana shops to post warnings for pregnant and nursing women has been rejected by Republicans who considered the requirement unfair. A bill to require the stores to post maternal warning signs had the support of some Republicans and the state Health Department. But a Senate committee voted 5-4 yesterday to reject the idea. Majority Republicans on the committee said it’s not fair to require maternal warnings in pot shops but not liquor stores. Recreational marijuana products sold in Colorado pot shops already contain warning labels about maternal pot use, similar to the labels on alcohol and tobacco. But the stores themselves do not have to warn customers that pot poses risks to children.