A union representing teachers in a suburban county near Denver has advised teachers how to destroy the evidence when they survey students about their gender identity and preferred pronouns, which is illegal under state law.

"If you do a questionnaire, please make it a paper and pencil activity – any digital records are more permanent and may be requested under federal law," the Jefferson County Education Association told teachers in an email.

A report by CBS explained parents raised the issue about teachers "breaking state and federal laws and their union is helping them get away with it."