Human Rights Watch has demanded that Iranian authorities either charge or release two doctors famous for their work in preventing and treating HIV/AIDS, BBC News reports ( 7/22).

Arash Alaei and Kamyar Alaei were detained last month. Their participation at the International AIDS Conference—beginning August 3 in Mexico City—is uncertain.

The brothers have been credited with pushing the Iranian government to tackle HIV stigma in a nation where drug abuse and sex are subjects not easily discussed.

A Human Rights Watch spokesperson said Iran’s work, largely under the guidance of the Alaei brothers, is internationally acclaimed. However, the brothers’ detention was damaging Iran’s reputation in the international AIDS community.