Samantha Power testified before House subcommittee on Tuesday
Hearing expected to continue through Thursday
MPs voted to repeal provision of 1969 law
MPs last month passed Anti-Homosexuality Act
Country's Supreme Court earlier this year ruled against marriage equality
Adam Michael Nettina voicemail referred to Nashville school massacre
Manhattan grand jury indicted former president for 2016 hush payments
House Ethics Committee investigating embattled N.Y. congressman
Queer Youth Assemble organized events across the country
Statement comes against backdrop of anti-transgender laws
