Many trans people are asked questions about what surgeries they’ve had all the time, and often the people asking are being inappropriate and have no business knowing about their genitals. This constant sexual harassment can have a profound negative effect on a person.
Before you ask a trans person about surgeries, ask yourself whether you’re in a situation in which you’d ask a cis person about their genitals.
Of course, if people are discussing a potential hook up, it might be an appropriate time to ask. But even if it is, asking something else that’s broader like “What are you into sexually” may open the door to the discussion without associating you with the people who ask in an offensive way.