The Boy Scouts of America will allow girls into its ranks for the first time in its nearly 100-year history, its leaders announced Wednesday, the latest move to adapt the organisation’s rules in an era of declining membership. The organisation said that its board unanimously approved the decision to allow girls into its Cub Scout programme, with plans to develop other programmes for older girls in the coming years, after years of requests from families and girls themselves. It is yet another policy shift for an organisation that long resisted substantial change to some of its rules and traditions, most notably a prohibition against openly gay scouts and leaders. The Boy Scouts ended those bans for scouts in 2013 and for leaders in 2015, which drew strong rebukes from the Mormon church and other religious groups. Earlier this year, the Boy Scouts took steps to allow transgender boys into its ranks. Chief Scout Executive Michael Surbaugh described the latest decision in part as an attempt to bring more families into the Boy Scouts, whose membership has declined by about a third since 2000. “The values of Scouting – trustworthy, loyal, helpful, kind, brave and reverent, for example – are important for both young men and women,” he said in a statement Wednesday. “We strive to bring what our organisation 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 company cited studies showing that cultural and economic factors made programmes that could serve both boys and girls more appealing to modern families. The changes will begin in 2018, when girls will be able to be enrolled as Cub Scouts. Eventually the programmes will be extended so that girls will be able to earn the rank of Eagle Scout, the organisation’s highest ranking. The Boy Scouts, founded in 1908 in Britain and in the United States two years later, has for decades been one of the country’s most prominent youth programmes focused on character building through teamwork, outdoor skills and other activities. Still, it was long the target of progressive ire for refusing to change rules it followed for decades that prevented gay youths and leaders from joining the organisation. The Boy Scouts still finds itself in the national spotlight from time to time. In July, a speech that US President Donald Trump delivered to thousands of Scouts – in which the president flouted the organisation’s traditions by criticising his opponents, gloating about his election victory and sharing stories about yacht parties – prompted its chief Scout executive to issue an apology. And deliberations about opening its membership to girls drew a heated letter from the Girl Scouts of America, which has also seen its membership decline in recent years.