By Caroline Stauffer and Mitra Taj
SANTIAGO (Reuters) - When Chile's President Michelle Bachelet leaves office in March, it will mark the end of a generation of women leaders in Latin America, leaving the region without a female head of state as it shifts to the right politically.
At the start of this decade, women held the top jobs in Argentina, Brazil, Costa Rica and Chile, collectively representing about 40 percent of the population in a region better known for its machismo.
But conservative Sebastian Pinera's victory in the second round of Chile's presidential election on Sunday drew that period to a close.
Bachelet was the first of her female counterparts to rise to power in a leftist tide that swept South America during a commodities-fuelled economic boom. She served as president from 2006 to 2010 before winning re-election in 2013.
Together with Brazil's Dilma Rousseff and Argentina's Cristina Fernandez, Bachelet embodied the major strides made by women across a region that has passed laws deterring rampant violence against women and set quotas for political participation that have given Latin American women a bigger share of parliamentary seats than in Europe.
But now some worry that progress on women's rights could stall.
"We're seeing a shift to conservative politics that is questioning the advances of the last 15 to 20 years," said Eugenia Piza-Lopez, who works on gender in Latin America for the United Nations Development Program.
Conservative groups are targeting gender equality across the region, said Piza-Lopez. Protests over curriculums aimed at empowering girls to rise above traditional female duties have helped topple education ministers in Peru and Colombia.
During campaigning in Chile, Pinera voiced concerns about the country's declining birth rate as he took aim at changes to abortion laws under Bachelet, who loosened a strict ban to make exemptions for rape, unviable fetuses and the risk of death during labour.
While there is no definitive study showing female leaders do more to advance women's wellbeing than men, Farida Jalalzai, a political scientist at Oklahoma State University, said her research on Latin America suggested that was the case.
"Dilma (Rousseff), for example, would take a policy that was already in existence and reframe it in ways that made it clear it was a women's issue, whether it was poverty or home ownership," Jalalzai said.
Piza-Lopez said Fernandez, who ruled Argentina from 2007 to 2015, helped narrow the gender poverty gap with her generous spending on social programs aimed at women.
Stella Zervoudaki, head of the European Union delegation in Chile, pointed to Bachelet's creation of a ministry of women, her programs to finance companies led by women and work for marriage equality.
"I'm not sure this would have been as forceful without a woman leader," Zervoudaki said. She said Bachelet had pressed for a chapter on gender in an update to an EU trade agreement that called for progress on equal pay, fair maternity leave and better access to technology for women.
In a region where corruption scandals often hurt presidencies, South America's women leaders were no honourable exception.
Rousseff was removed from office in 2016 on accusations she manipulated budget laws and was later charged with graft. A judge in Argentina has charged Fernandez, now a senator who is also under investigation for graft, with treason for allegedly covering up Iran's possible role in a 1994 bombing.
Both women deny wrongdoing. Rousseff recently visited Fernandez in her apartment in Buenos Aires to commiserate, and has said sexism played a role in her own impeachment.
Brazil's conservative President Michel Temer appointed an all-male cabinet after Rousseff's exit. She was voted out after lawmakers held up signs saying "bye, dear!"
In contrast, Pinera said on Monday he would announce the "women and men" who would form his team, a sign he would create a balanced cabinet, perhaps taking his lead from Bachelet, whose first cabinet was exactly half men and half women.
Bachelet's own approval ratings were hit hard after her daughter-in-law was accused of using political ties to get access to a bank loan.
Although Latin America is poised to hold six elections next year - in Costa Rica, Paraguay, Colombia, Venezuela, Mexico and Brazil - the chances for another female president are slim.
In Mexico, leftist frontrunner Andres Manuel Lopez Obrador has repeatedly referred to his rival Margarita Zavala as "the wife of Felipe Calderon" - her husband and a former president - angering her supporters, who charge it is sexist. She is polling around 10 percent of votes.
In Brazil, Marina Silva, who has lost the presidency twice, recently joined the race and lies third in most polls.
A number of female candidates are expected to compete in Colombia's presidential race, though none is expected to win. Maria Eugenia Vidal, the governor of Argentina's largest province of Buenos Aires, is the country's most popular politician, according to several polls, but is not expected to run for president in 2019.
Still-rampant sexism and sexual harassment in politics remain deterrents to women who want to rise to the top, said Mercedes Araoz, Peru's Prime Minister and a former presidential candidate.
"I've been a victim (of sexual harassment)," Araoz recently told journalists. "It's important to realize how discouraging it can be."
(Reporting by Caroline Stauffer and Mitra Taj, Additional reporting by Dave Graham in Mexico City; Editing by Daniel Flynn and Rosalba O'Brien)