The American Family Association (AFA) has urged its members not to accept mail postmarked with the new Harvey Milk stamp.
Milk, played by Sean Penn in an eponymous 2008 biopic, was one of the first openly gay politicians to be elected to public office in the US; winning a seat on the San Francisco Board of Supervisors in 1977.
After serving just 11 months in office, during which time he was a key advocator for the rights of minority groups and successfully passed a Gay Rights Ordinance that offered greater protections in the workplace for gay people, Milk was assassinated by Dan White; a former colleague who had grown dissatisfied with the political system and who frequently clashed with Milk over issues pertaining to gay rights.
Milk is now widely considered a civil rights hero, and President Obama posthumously awarded him the Medal of Freedom in 2009. The state of California holds an annual "Harvey Milk Day" on May 22 to recognise the murdered politician's efforts to promote equality.
On May 22 this year, the US Postal Service released a commemorative stamp featuring Milk's iconic image, but a conservative Christian group – which contends that Milk "repeatedly engaged in adult-child sex" – is now calling on its followers to boycott mail sent with the stamp; branding the use of the politician's portrait as "disturbing".
"Honouring predator Harvey Milk on a US postage stamp is disturbing to say the least," AFA President Tim Wildmon said in a statement.
"Harvey Milk was a very disreputable man and used his charm and power to prey on young boys with emotional problems and drug addiction. He is the last person we should be featuring on a stamp."
The statement continues: "The radical homosexual lobby will undoubtedly encourage businesses to use these stamps – all in the name of inclusiveness, political correctness and unity.
"Whatever you think about diversity, no one thinks diversity ought to include paedophilia. This is not diversity; this is perversity."
The AFA recommends that people refuse to use the Harvey Milk stamp, instead using one featuring the US flag, and also return mail postmarked with the stamp to the sender.
Not everyone has deemed the stamp offensive, however. According to the Bay Area Reporter, the stamp sold out on its first day in Castro, San Francisco.