The Boy Scouts of America announced on Wednesday its plans to admit girls into the Cub Scouts and create a new program for older girls to allow them to earn the highest rank of Eagle Scout, a historic change after years of requests from families and girls.

The change is expected go into effect in 2019. Cub Scout dens, the smallest unit, will become single-gender, either containing all boys or all girls. The larger Cub Scout packs will have the option to welcome both genders if they choose.

“We believe it is critical to evolve how our programs meet the needs of families interested in positive and lifelong experiences for their children,” the Boy Scouts said in a news release.

“We strive to bring what our organization does best – developing character and leadership for young people – to as many families and youth as possible as we help shape the next generation of leaders," the release stated.

The program for older girls is expected to be announced in 2018 and begin in 2019. Girls will then be able to earn the coveted rank of Eagle Scout.

Boy Scout leaders also cited busy and diverse families as a reason to make the change. They hope the switch would give parents more options. Boy Scouts began offering co-ed programs in 1971. It will be celebrating its 20th anniversary next year.

The Girl Scouts organization has criticized the initiative, saying it strains the century-old bond between the two groups.

The Associated Press contributed to this report.