As the skull-and-crossbones symbol has also entered popular culture in the context of piracy, and since cartoonish pirates have become popular characters with children, there have been concerns that the "poison" symbol might have the effect of attracting the curiosity of small children familiar with "pirates" as depicted as a toy or play theme. For this reason, in the United States there has been a proposal to replace the skull and crossbones by the "Mr. Yuk" symbol. However, Mr. Yuk and his graphic rendering are registered trademarks and service marks of his creator, the Children's Hospital of Pittsburgh of UPMC, and the rendering itself is additionally protected by copyright.