The Big Sister Association of Greater Boston has sued Big Brothers Big Sisters of Massachusetts Bay over an alleged trademark infringement, reports The Boston Globe. The Big Sister association alleges that Big Brothers’ decision to add “Big Sisters” to its name last year has created public confusion about the groups’ identities and has hurt Big Sister’s fund-raising efforts.

The two organizations discussed the name change over the course of the past year but were unable to resolve the dispute.

Said Deborah Re, chief executive of the Big Sister Association of Greater Boston, “My responsibilities to raise money and increase visibility are both being hindered by Big Brothers’ name grab of ‘Big Sister.’”

John B. Pearson, chief executive of Big Brothers Big Sisters of Massachusetts Bay, called the lawsuit “very disappointing.”

Big Sister group was founded in 1951 to provide advice and support to young girls in the Boston area, is one of only two regional branches still in existence. Most others have merged with local Big Brothers chapters.

Big Brothers of Massachusetts Bay was founded in 1949. It began providing services to girls in 1998.