Fresh from failing to prevent an Archie comic featuring a gay marriage from being sold in America, conservative American mothers' group One Million Moms has launched a new attempt to stamp out homosexuality from the world of graphic novels.

The American Family Association-run conservative Christian organisation has taken issue with the news that DC Comics is planning to reveal that one of its established characters is gay – speculation is centring around Batman, Green Lantern and Wonder Woman – and that Marvel's new issue of Astonishing X-Men will feature Northstar's marriage to his boyfriend. "Here are two people, trying to live their lives – mutant and gay, black and gay – empowered in their own ways, but also fringe-dwellers," author Marjorie Liu told Rolling Stone earlier this month. "And they're making it happen. They're living life on their own terms. It doesn't matter that it's a superhero comic, the message is: You can do the same thing."

This is not, something One Million Moms approves of. "Children desire to be just like superheroes. Children mimic superhero actions and even dress up in costumes to resemble these characters as much as possible. Can you imagine little boys saying, 'I want a boyfriend or husband like X-Men?'" says the organisation. "This is ridiculous! Why do adult gay men need comic superheroes as role models? They want to indoctrinate impressionable young minds by placing these gay characters on pedestals in a positive light. These companies are heavily influencing our youth by using children's superheroes to desensitise and brainwash them into thinking that a gay lifestyle choice is normal and desirable. As Christians, we know that homosexuality is a sin."

Members are writing to DC Comics and Marvel to ask them "to change and cancel all plans of homosexual superhero characters immediately". Whether the move will have the effect that the mothers desire remains to be seen: following One Million Moms' campaign to stop Toys R Us selling the Archie comic, which featured the marriage of Kevin Keller, the series' first gay character, the issue sold out.

Comic writers were unimpressed by the campaign. "Dear @1milmoms, thank you for the boycotts. They increase sales as people buy extra copies to spite you. PLEASE boycott my book too. :-)" tweeted Spider-Man author Dan Slott. "One Million Moms: There aren't a million of them and their board is mostly men. If they lie about who they are, they'll lie about anything," said comics author Kurt Busiek.

Marvel Comics editor-in-chief Axel Alonso said in a statement to Newsarama: "For over 70 years, Marvel's comics have reflected the world outside your window and Astonishing X-Men #50 carries on that tradition. We're proud to create stories that are not only relevant to the issues facing a modern audience but that also explore these nuanced subjects in a compelling manner. We've planned the release of this comic for over a year but the recent discussion of gay marriage, spurred by the comments of President Obama, makes the release of Astonishing X-Men #50 even more timely. The passionate discourse between our fans on both sides of this matter shows that we've struck a chord with our millions of fans around the world."