Gay-rights activists are waging an online campaign to persuade some of the country’s biggest retailers, including Apple, Microsoft, and Wal-Mart, to end their association with an Internet marketing firm that gives a portion of its proceeds to charities, among them prominent Christian right groups, says The New York Times.

The firm, Charity Giveback Group, earns commissions from companies to which it steers online customers, a routine arrangement in the world of Internet shopping.

People who buy goods through the affiliate firm can donate a portion of the commission to a variety of Christian charities. Among those nonprofit groups are the Family Research Council and Focus on the Family.

Gay-rights advocates and the Southern Poverty Law Center contend such groups demonize gays and lesbians in pursuing conservative policies.

Microsoft and Apple, both targets of the online petition campaigns, have withdrawn from deals with the Charity Giveback Group. Similar campaigns have focused on the travel industry.

Christian groups have started their own campaigns in support of Charity Giveback Group, accusing gay-rights advocates of anti-Christian bias.

John Higgins, president of Charity Giveback Group, said critics “have been misled” into thinking retailers are directly donating to the evangelical groups.

“They are simply paying a commission to get traffic,” Mr. Higgins said of his firm’s corporate clients. “Retailers should keep their doors open to everybody.”