WASHINGTON—The director of the Centers for Disease Control and Prevention on Tuesday suggested a Trump administration proposal that would define someone’s sex at birth risked heightening stigma around transgender people.

The director, Robert Redfield, did not directly criticize the proposal. But when asked whether any such effort might hamper efforts to treat HIV, especially among transgender women, he replied: “We need to understand that stigmatizing illness, stigmatizing individuals is not in the interest of public health.”

He made the remarks in an interview with STAT Executive Editor Rick Berke at the opening session of the Milken Institute’s Future of Health Summit.

Redfield said he was not involved in developing the policy, which was first reported by the New York Times.

The proposal was criticized by scientists, who pointed out that it stands in contradiction to basic biology, which recognizes that many individuals are born with sex chromosomes or genitalia that don’t conform to the social definitions of “male” and “female.”

Trump addressed the issue Monday, telling reporters that the administration is “looking at it.”

“We have a lot of different concepts right now,” Trump said. “They have a lot of different things happening with respect to transgender right now. You know that as well as I do and we’re looking at it very seriously.”

The Department of Health and Human Services, which oversees the CDC, has declined to comment on the substance of the proposal directly. On Monday, the Washington Post reported that, while HHS is backing the proposal, the Department of Education is pushing back.

Redfield also argued that stigma is harmful more broadly, saying that it interferes with actually treating a disease, such as addiction to opioids.

He said that the stigma around opioid use now is greater than the stigma around AIDS.

“It’s nothing compared to what we’re confronting with drug use,” Redfield said.

For him, the issue is personal—his son has been in recovery for drug use for three years.

“I pray for him every day,” Redfield said. “People don’t realize that addiction is a medical condition, it’s not a moral failing. People don’t realize it’s a chronic medical condition.”

Redfield compared it to another disease, like cancer. We don’t stigmatize people whose cancer goes into remission and then flares back up, he said, so why do we stigmatize people who relapse after treatment for drug use?

He said that treatment for addiction should be integrated into primary care.

Republished with permission from STAT. This article originally appeared on October 23, 2018