The presidential election in the United States this year is, yet again, a contest between two men. But in Latin America, as Mexico’s milestone election showed over the weekend, electing a woman as president has become remarkably routine.

Claudia Sheinbaum, who won Mexico’s election in a landslide against another female candidate, Xóchitl Gálvez, joins at least a dozen other women who have served as presidents of Latin American countries since the 1970s.

This growing list includes past leaders of two of Latin America’s largest countries, Dilma Rousseff of Brazil and Cristina Fernández de Kirchner of Argentina, and those in smaller nations like Violeta Chamorro of Nicaragua and Xiomara Castro, the current president of Honduras.

The ascension of women to such heights spotlights how some democracies in Latin America that emerged from the ashes of authoritarian rule have proven exceptionally open to tearing down barriers to political representation.

Jennifer Piscopo, a professor of gender and politics at Royal Holloway, a college at the University of London, said that women who had become president in Latin America generally followed a pattern of being nominated by incumbent parties already enjoying high levels of voter support.

Citing the examples of Ms. Rousseff in Brazil, Michele Bachelet in Chile and Laura Chinchilla in Costa Rica, Ms. Piscopo said such parties “enjoy the best of both worlds,” first by reaping electoral benefits from their strong reputation going into an election.