The statement followed a report in The Times that a federal health official had urged the removal of age minimums from treatment guidelines for transgender minors.
A procedure called top surgery performed on a 14-year-old in California in 2015. Surgery for transgender minors remains exceedingly rare, studies have shown.
The organ, from a genetically modified animal, failed because of a lack of blood flow, surgeons said, but did not appear to have been rejected by the body.
A new analysis of dozens of studies has identified the most common warning symptoms in adults under 50, whose rates of colon and rectal cancer are on the rise.