Underrepresentation is just one factor that reduces visibility. Unlike women and minorities, whose status is usually obvious, sexual orientation is a hidden characteristic. The fact that a sizable proportion of the L.G.B.T. STEM work force is closeted (43 percent, according to a 2015 estimate) further deepens this effect.

There is a another, more insidious factor at work. STEM culture is very problem-focused. Conversations, even over lunch, typically remain restricted to work matters (which is very different from what I’ve noticed in arts and humanities settings). A colleague who studied in the math department at Spelman College tells of a surreal afternoon on Sept. 11, 2001, when her professor placidly delivered his scheduled lecture on set theory without once mentioning the attacks.

Being too expressive of personal identity can be viewed as running counter to scientific neutrality. In competitive venues, where complete immersion in one’s field might be the promoted ideal, the mention of an extracurricular pursuit can even be seized upon as a lack of commitment. I remember a young mathematician at a prestigious research institute sharing his love for piano playing after hearing I wrote fiction. “Don’t tell anyone in my department I own a piano,” he requested in the next breath.