Mary Going, 46, a former nonprofit consultant in Oakland, Calif., wanted to wear a suit to her same-sex wedding in 2008, but found the shopping process demoralizing.

Nothing fit. Sometimes there were no dressing rooms. And salesmen looked at her funny when they realized she wasn’t shopping for a son. “They didn’t want to be serving me,” Ms. Going said. “You can feel it.”

She soon learned that she was not alone, and in 2012, Ms. Going started an online suit store, Saint Harridan, that specializes in classic men’s suits tailored for women. It joins a fresh crop of untraditional fashion brands and style blogs that cater to butch lesbians, transgender men, the androgynous and tomboys — underserved customers who might call themselves “masculine of center,” a gender-studies term for women who dress and act in ways traditionally associated with men.