An investigation has been launched after leaflets that criticised plans for the lesbian, gay and bisexual Mardi Gras in Anglesey were circulated to families.
Local councillors say the document is "extremely offensive" and could fall foul of the Equality Act, but Christian Voice, which is responsible for the leaflets, says it is freedom of speech.
Police are looking into the matter after a number of local people complained to the town's council.
The Mardi Gras, taking place next month, is in its second year and organisers have coined it, "The Largest Gay event ever in the History of the north Wales gay community."
Christian Voice said on its website that if the event does go ahead, "the narrow streets of Beaumaris are perfect for preaching and one-to-one conversations."