Using hormones to treat transgender children who feel that they are members of the opposite sex, which is becoming commonplace in medicine, could have serious long-term effects on children, doctors are warning in a new report.

In a paper published in the journal The New Atlantis this week, Paul Hruz of the Washington University Medical School and Lawrence Mayer and Paul McHugh of Johns Hopkins Medical School say such treatments could have serious health implications, the New York Post reports.

The paper, called “Growing Pains: Problems with Puberty Suppression in Treating Gender Dysphoria,” notes a recent analysis by UCLA found that about 1.4 million people in the United States identify as transgender, a growing number of whom are children.

The number of children diagnosed with “gender dysphoria” — described by clinicians as “incongruence between one’s experienced/expressed gender and assigned gender” — has been on the rise.

A gender identity clinic for children in the United Kingdom, for instance, reported a 2,000 percent increase in referrals since 2009, with those for children under the age of 6 going from six to 32 in the same time period.

Well-meaning parents have been increasingly trying hormone suppression, which prevents sex organs in boys and girls from developing in the usual way, Hruz, Mayer, and McHugh note.

While that may allow children to postpone decisions about actual sex-reassignment surgery, the authors argue that this therapy may have real and long-term effects on children’s physical and psychological development.

“Whether blocking puberty is the best way to treat gender dysphoria remains far from settled,” they write, “and it should be considered . . . a drastic and experimental measure.”