A California group campaigning to “protect marriage” is suing a gay rights organisation for parodying its logo.

ProtectMarriage.com has launched a lawsuit against Courage Campaign for trademark infringement and unfair competition.

The original logo showed the figures of a mother, father and children holding up a banner saying “Yes On 8 Protect Marriage”. The logo was used in the 2008 campaign to ban gay marriage in the state.

Courage Campaign has parodied the logo for its online Proposition 8 trial tracker. The parody shows two female figures with children.

The tracker follows the progress of the current trial on gay marriage in California.

However, ProtectMarriage.com did not see appreciate the joke and sent a cease-and-desist letter to Courage Campaign.

When the gay rights group ignored the letter, it filed a lawsuit.

Courage Campaign poked fun at the lawsuit in a blog entry yesterday: “We continue to be entertained by the Prop 8 attorneys simultaneously admitting that the two images of gay parents and straight parents are ‘substantially indistinguishable’, and yet failing to grasp that the difference between the logos illuminates the core difference between their views and ours.”

In a ruling yesterday, Judge Lawrence K Karlton denied ProtectMarriage.com’s motion for a temporary restraining order prior to a full ruling.

ProtectMarriage.com argued that a ruling was needed quickly before the trial ended.

According to the Sacramento Bee, Karlton said: “In this case, the logo itself is artistic. Moreover, the broader website, while perhaps not artistic, is undeniably expressive of a political idea, and both political and artistic expression are protected by the First Amendment.”