The Biden administration said this week that it opposed gender-affirming surgery for minors, the most explicit statement to date on the subject from a president who has been a staunch supporter of transgender rights.

The White House announcement was sent to The New York Times on Wednesday in response to an article reporting that staff in the office of Adm. Rachel Levine, an assistant secretary at the Department of Health and Human Services, had urged an influential international transgender health organization to remove age minimums for surgery from its treatment guidelines for minors.

The draft guidelines would have lowered the age minimums to 14 for hormonal treatments, 15 for mastectomies, 16 for breast augmentation or facial surgeries, and 17 for genital surgeries or hysterectomies. The final guidelines, released in 2022, removed the age-based recommendations altogether.

“Adm. Levine shared her view with her staff that publishing the proposed lower ages for gender transition surgeries was not supported by science or research, and could lead to an onslaught of attacks on the transgender community,” an H.H.S. spokesman said in a statement on Friday evening.

Federal officials did not elaborate further on the administration’s position regarding the scientific research or on Adm. Levine’s role in having the age minimums removed.

The administration, which has been supportive of gender-affirming care for transgender youth, expressed opposition only to surgeries for minors, not other treatments. The procedures are usually irreversible, critics have said.

Medical care for transgender adolescents has become a hot-button issue in many states, particularly in conservative political circles. The Texas Supreme Court on Friday upheld a state law banning all gender-affirming medical treatment for minors.

The Supreme Court agreed on Monday to hear a challenge — brought in part by the Biden administration — to a Tennessee law that bans treatments including puberty blockers, hormone therapy and surgery for transgender minors. This will be first time the justices will decide on the constitutionality of such statewide bans.

The Biden administration’s previous statements on gender-affirming care for minors have not in the past explicitly opposed surgery.

A two-page explainer on gender-affirming care that is frequently cited by federal officials stated that gender-affirming surgeries were “typically used in adulthood or case-by-case in adolescence,” leaving the door open to surgery for minors in some instances.

Other gender-affirming treatments such as reversible puberty blockers are used during puberty, the explainer noted. Hormone treatments with estrogen or testosterone, which are partly irreversible, are used in “early adolescence and onwards,” it said.

Despite the outsize attention the issue has drawn, it is rare for minors in the United States to undergo gender-affirming surgeries.

The procedures include “top” surgeries to remove or augment the breasts, “bottom” surgeries on genitals and reproductive organs, and other operations to modify facial features.

Breast reductions or mastectomies for transgender men and nonbinary individuals are the procedures done most frequently. Some doctors have argued that minors should have access to breast surgery before age 18 because breast development takes place early in puberty and the breasts are so visible that transitioning teens go to great lengths to conceal them, often binding their chests.

But even as the number of minors having these operations has risen in recent years, they continue to be extremely uncommon.

The number of annual chest procedures for minors covered by insurance in the United States is estimated to be in the hundreds. While there are no official statistics, a national analysis of hospital data from 2016 through 2020 identified about 3,600 patients from the ages of 12 to 18 who had gender-affirming surgery.

A vast majority were chest-related, an increasingly common procedure among transgender teens.

An analysis of one hospital’s data found that the number of gender-affirming mastectomies in insured teenagers increased from five cases in 2013 to 70 in 2019. But genital surgeries among minors are “exceedingly rare,” doctors have reported.

The administration has been a strong supporter of transgender people, affirming individual rights to gender-affirming care, highlighting federal provisions protecting transgender Americans against discrimination, and emphasizing the importance of mental health services for transgender youth.

The Biden administration has condemned state legislation targeting transgender people. It has allowed passport holders to use an “X” to describe their gender, and taken steps to combat violence against transgender individuals.

After Florida proposed a number of laws targeting transgender residents in 2023, including measures that would ban gender-affirming care for minors and restrict transgender athletes from joining certain sports teams, Mr. Biden said he found the efforts “terrible.”

He did not specify the particular policies with which he disagreed. In contrast, Donald J. Trump, the presumptive Republican nominee for president, announced a plan in a video posted in 2023 on Truth Social to pass a federal law banning all gender-affirming care for minors, which he described as “child sexual mutilation.”

He also said any hospitals that perform the treatment would be ineligible for Medicaid and Medicare funds under this policy.