CAIRO — Pop star Katy Perry’s “I Kissed a Girl” was playing on speakers set around the dimly lit dance floor. Kholoud Bidak, a 33-year-old lesbian, leaned against an old piano, scanning the entrance warily as guests paid $6 to get into one of Cairo’s increasingly common underground gay parties.

Just months ago, a raid by Egypt’s vice police would have been a concern at gatherings such as this fete for a man in red shorts who was turning 26. But on the recent sweltering Thursday night, as men in pastel-colored, V-neck T-shirts streamed in, a crackdown was the last thing on Bidak’s mind. She worried whether a certain woman might walk through the door.