Republican presidential candidate Rick Santorum has angered gay rights activists in the United States after he told a boy not use a pink bowling ball during a campaign photo opportunity at a Wisconsin bowling alley.

Reuters journalist Sam Youngman reports that Mr Santorum told a boy to avoid using a pink ball. “You’re not going to use the pink ball. We’re not gonna let you do that. Not on camera.”

Prompted by a journalist for why he said it, Mr Santoru replied “friends don’t let friends use pink balls.”

“This is another example of Rick Santorum intentionally making ignorant statements that have a real impact on LGBT people,” said Human Rights Campaign (HRC) Vice President of Communications Fred Sainz. “Whether he’s comparing our marriages to inanimate objects, saying our children would be better off with a parent in prison as opposed to two loving same-sex parents, or calling open military service a ‘tragic social experiment;’ he’s proven that he thinks LGBT people are second-class citizens not worthy of dignity or respect. In this case, he’s advancing tired gender norms by implying a boy should be ashamed or embarrassed to use a certain colour bowling ball.”

In January, Mr Santorum suggested that children of lesbian parents were “worse off than children with a father in prison.”

Last week, Mr Santorum said he would pray for the creator of the It Gets Better campaign, Dan Savage: “I would tell him [Savage] that I’m praying for him. He obviously has some serious issues. You look at someone like that who can say and do the things that he’s doing and you just pray for him and hopefully he can find peace.”

Mr Savage launched the hugely successful It Gets Better project to combat LGBT teenage suicide which has featured major figures ranging from Lady Gaga to president Obama.

He also launched a tongue in cheek campaign back in 2003 to redefine ‘Santorum’ on Google as “the frothy mix of lube and fecal matter that is sometimes the byproduct of anal sex.”

Responding to Mr Santorum’s offer to pray for the columnist and campaigner, Mr Savage told MotherJones.com: “Rick Santorum thinks that women who have been raped should be compelled—by force of law—to carry the babies of their rapists to term, he thinks birth control should be illegal, he wants to prosecute pornographers, etc., etc., basically the guy wants to be president so that he can micromanage the sex lives of all Americans…and I’m the one with issues? Because I made a dirty joke at his expense eight or nine years ago and it stuck? I’m the one with issues? Rick can pray for me. I’ll gay for him. And we can call it even.”

Last month, activists created a portrait of the Republican candidate made entirely out of gay pornography.