Citing years of research and feedback from Scouts nationwide, officials from the group said that Cub Scout dens — the smallest unit — will be single-gender, either all boys or all girls. Cub Scout packs, which are larger and include a number of dens, will have the option to welcome both genders if they choose. The group's board of directors voted unanimously in favor of the changes.
"This decision is true to the BSA's mission and core values outlined in the Scout Oath and Law. The values of Scouting — trustworthy, loyal, helpful, kind, brave and reverent, for example — are important for both young men and women," Michael Surbaugh, chief executive of the Boy Scouts of America, said in a statement.
"We believe it is critical to evolve how our programs meet the needs of families interested in positive and lifelong experiences for their children. 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," he said.
The program for older girls is expected to start in 2019 and will enable girls to earn the coveted rank of Eagle Scout.
For decades, the Boy Scouts' Explorer program has allowed limited participation by girls, but Wednesday's announcement expands their involvement. Since 1971, the group has offered coed programs in exploring and venturing.
The shift by the Boy Scouts comes as the group has found itself embroiled in larger national debates about gender roles and sexual orientation. These debates, in turn, have led the Boy Scouts — which has about 2.3 million members — to examine long-held policies that date to its founding.
More recently, a rift has emerged between the two groups.
In August, Kathy Hopinkah Hannan, the president of the Girl Scouts, sent a letter to the Boy Scouts of America accusing the group of carrying out a "covert campaign to recruit girls into programs" in the hopes of bolstering declining membership. Hannan wrote that it was "reckless" and shortsighted in "thinking that running a program specifically tailored to boys can simply be translated to girls."
On Wednesday, officials from the Girl Scouts did not immediately respond to a request for comment. However, the organization issued a statement that implicitly challenged the Boy Scouts' decision without mentioning it.
"The need for female leadership has never been clearer or more urgent than it is today — and only Girl Scouts has the expertise to give girls and young women the tools they need for success," the statement says. "We're committed to preparing the next generation of women leaders, and we're here to stay."
One individual close to the Girl Scouts, who requested anonymity to speak freely about the group's concerns, said that it believes the policy shift by the Boy Scouts is an effort to increase a membership that has declined by nearly a third since 2000.
Still, the move was widely viewed as long overdue and received praise.
Sydney Ireland, 16, who lives in New York City, is a member of Scouts Canada, which for several years has allowed girls. She started a change.org petition in 2015, calling on the Boy Scouts to allow her to enroll. To date, it's attracted nearly 9,000 supporters.
"This change is amazing … it really is," Sydney said. "People ask, 'Why as a girl do you want to be a Boy Scout?' I say because Girl Scouts don't offer all the programs that the Boy Scouts do. … I just have an interest in the different programs that the Boy Scouts offer."
Sydney said she plans to join Boy Scout Troop 414 in New York, a troop that she currently participates in as an unofficial member.
The Boy Scouts of America, founded in 1910 for boys and their male leaders, focuses on promoting responsibility through an array of outdoor activities and educational opportunities.
In the 1980s, Catherine Pollard, a mother from Milford, Conn., sued the group to overturn the ban against female Scoutmasters, alleging it violated sex discrimination laws. The lengthy legal proceedings — which went on for nearly a decade — drew international attention, and courts ultimately sided with the Boy Scouts.
Even so, Pollard's fight caught the public imagination, and in 1988, as the Boy Scouts faced mounting criticism from civil rights groups, the group's national executive board voted to allow women in leadership positions — including Scoutmaster. Pollard became the first female Scoutmaster, and today, according to the Boy Scouts, nearly a third of the group's volunteers are women.
More recently, the Boy Scouts have offered entry to new members who had previously been banned based on decades-old policies.
In 2010, the group's executive board began what would become a two-year review of its policy on gays. Three years later, as the group faced criticism from lesbian, gay, bisexual and transgender rights groups, the Boy Scouts formally announced an end to its ban on gay Scouts.
And in January, the Boy Scouts announced that it would allow transgender children who identify as boys to enroll in its boys-only programs. At the time, Surbaugh said, "communities and state laws are now interpreting gender identity differently than society did in the past," which is reflected in the group's reasoning for the change.
Zach Wahls, Eagle Scout and cofounder of Scouts for Equality, called Wednesday's decision to allow girls into the group a "step forward." His group has pressed the Boy Scouts to allow gay and transgender children. He said he still would like to see the group end its ban on atheists and agnostics. But, he said, Wednesday's announcement signaled an important change.
"Girls and their families across the country have been asking for decades to participate," Wahls said. "Now, girls are going to be able to have the Scouting experience. …This is progress and overdue."
5:35 p.m.: This article has been updated with a statement from the Girl Scouts.
3:55 p.m.: This article has been updated with quotes, description of the Explorer program and other details.
11:55 a.m.: This article has been updated with details of Girl Scout dispute, quotes, background.
11:10 a.m.: This article has been updated with staff reporting.