“It’s easier to not know where I’m going to end up than to come to Mexicali. I can’t be myself here,” she said as the bus made its way toward the international border crossing at Calexico, Calif. If she wants to be safe in Mexico, she said, “this is how I have to be.”

Intolerance toward homosexuality and nontraditional gender identities are woven into the culture in parts of Mexico, where the Catholic Church, a powerful force, describes such orientations as sinful. Mexicali, a large city of one million, is not ultraconservative: The city has several gay and lesbian nightclubs, for instance. But even as cities across Mexico become more tolerant — with big gay and lesbian communities emerging in Mexico City and Oaxaca — transgender women are still treated with derision. Physical attacks are not uncommon, and they often go unpunished.

In California’s agrarian Imperial Valley, transgender women, many of whose extended families are just across the border in Mexicali, say they feel greater safety from physical violence and harassment because of American laws and cultural norms. Yet the question of simply moving to the United States is not a simple one, even for those, like Ms. Taylor, who have green cards. Life can be prohibitively more expensive compared with the cost of living in Mexico. And the Imperial Valley, one of the most fertile farm regions in the United States, can be rather quiet because it is so rural.