The Big Bang Theory is coming under fire for allegedly using Ellen Newlin Chase and Margaret Chase Perry mother’s copyrighted nursery rhyme, “Soft Kitty.” The two are also suing Warner Bros, CBS, creator Chuck Lorre, Turner Broadcasting, Fox, and anyone associated with the show.

The plaintiffs want damages and profits, costs and attorneys fees, prejudgment interest, other relief, and an immediate injunction from the companies listed above. The lawsuit was filed on Monday in the southern district of New York. It states that the defendants “never contacted or made any attempt to contact Edith Newlin or her successors to seek permission to use the Soft Kitty Lyrics, and Plaintiffs never granted any permission to do so.” It also states that “Soft Kitty” lyrics are copyrighted to the author.

The lyrics that were used in about eight different episodes of The Big Bang Theory are: “Warm kitty, soft kitty/Little ball of fur/Sleepy kitty, happy kitty/Purr! Purr! Purr!” The song was used to help Sheldon Cooper (Jim Parsons) fall asleep when he wasn’t feeling well.

Back in 2007, Warner Bros. Entertainment made a deal with Willis Music to use the lyrics on the show but the plaintiffs are stating that Willis Music never had a right to say that. The lyrics originally were used in Willis’ complication “Songs for the Nursery School” in 1937 but were only to be used for one time use.

The lawsuit also states that the lyrics were used for merchandise such as t-shirts, mouse pads, wallets, and cell phone covers. When the plaintiffs’ mother died in 2004, the rights to the lyrics were passed down to the daughters in Edith Newlin’s will.