NEW YORK, (Reuters) - Former U.S. President Jimmy Carter can still command people's attention. His 2009 column on why he quit his church for women's rights -- "Losing my religion over equality" -- has abruptly gone viral.

Carter, 90, a Nobel Peace laureate and longtime human rights champion, has campaigned to end violence and discrimination against women since leaving the White House in 1981, calling it "the human and civil rights struggle of our time".

Carter's campaign for the better treatment of women and girls globally has never stopped and last year his book, "A Call to Action: Women, Religion, Violence and Power," was published calling on world leaders for action.

Ensnared in religious beliefs and traditional customs that often trump civil law, women's rights are under constant assault across the globe, Carter told Reuters.

He has drawn up a list of 23 gender-based issues he wants addressed, from child marriage to honor killings - but for him, one is of particular worry.

"I would say the one that concerns me the most is the murder of little baby girls, the aborting of them when they're found to be female," he said, referring to the practice of sex-selective abortion in countries where there is a preference for sons.

"That's about the most horrendous of all the problems we're facing," he said in a telephone interview.

Due to these practices, there are some 160 million missing girls, primarily from India and China, but also from other countries, he said.

"These countries pass laws that prevent these abuses, but people just ignore the laws and the government looks the other way."

His fight for women's rights was sparked during his years travelling around the world when he became increasingly concerned about the myriad problems he saw involving women.

Carter, the 39th U.S. president who took up office in 1977, founded the Carter Center with his wife Rosalynn in 1982 dedicated to the protection of human rights, promotion of democracy, and prevention of disease.

His determination to promote the rights of women led him in 2000 to sever ties with the Southern Baptist Convention, after six decades, over its rejection of women in leadership.

He explained his decision to quit the church in a 2009 article titled "Losing my religion for equality".

"Women and girls have been discriminated against for too long in a twisted interpretation of the word of God," he wrote in the article.

A flood of people have viewed the article on the website of Australia's The Age newspaper -- the highest rated story in the publication's history -- after it was tweeted recently by a U.S. pastor and spiraled on social media. It has been shared over 900,000 times on Facebook and 1,400 times on Twitter.

"I've always admired the unusual decency & humility of former US Pres Jimmy Carter - movingly evident here, again," tweeted Australian Senator Penny Wright.