In this file photo, Cub Scouts watch a race during the Second Annual World Championship Pinewood Derby in New York's Times Square.(AP Photo/Mary Altaffer, File)

The Boy Scouts of America has announced it will allow transgender children who identify as boys to enrol in its boys only programmes.

The organisation said it has made the decision to base enrolment in boys only programmes on the gender a child or parent lists on the application to become a scout.

The Boy Scouts had previously relied on the gender listed on a child's birth certificate.

A spokeswoman for the organisation said it had made the decision based on states and communities changing how gender is defined.

Kristie Maldonado said she had mixed emotions when a Boy Scouts official called to tell her about its decision.

Her son, Joe, was asked to leave his New Jersey scout troop last autumn after parents and leaders found out he is transgender.

PA Media