For more than a century, the Boy Scouts of America has designated its members according to the sex described on their birth certificate.
But now that's changed, and it's ready to accept transgender boys.
"We've taken the opportunity to evaluate and update our approach," Chief Scout Executive Michael Surbaugh said. "I hope you'll join with me in embracing the opportunity to bring scouting to more families and children who can benefit from what our organisation has to offer."
The change in policy was likely prompted by a case in the state of New Jersey, where an 8-year-old child was asked to leave his Scout troop after the parents of other children discovered he was transgender.
TRT World correspondent Nafisa Latic has more.