An anti-gay group in the US is telling its members to return all mail with a Harvey Milk stamp.

In a 27 May blog post, the American Family Association rails against the US Postal Service stamp honoring the first openly gay man to be elected to public office in California.

‘Refuse to accept mail at your home or business if it is postmarked with the Harvey Milk stamp,’ AFA writes. 'Simply write “Return to Sender” on the envelope and tell your postman you won’t accept it.’