By the time Michael Hennessy Higgins left Ireland, he was already known as a free-thinker and atheist. So it wasn't out of the question that he could expect unusual things from his children and grandchildren.

Nevertheless, it would have been hard to predict that Higgins’ offspring would play a central role in a sexual revolution that produced not only the birth control pill, but also the legendary comic book character Wonder Woman.

As two new books and a forthcoming big-budget superhero movie prove, we are very much living in a world shaped by Higgins’ daughters, Margaret and Ethel.

Margaret is the better-known of the two. Born in Corning, NY she married an architect named William Sanger, and would forever be known as one of the leading women’s rights advocates in the early 20th Century.

As The New York Times noted in Margaret Sanger’s 1966 obituary, “The dynamic, titian-haired woman whose Irish ancestry also endowed her with unfailing charm and persuasive wit was first and foremost a feminist.”

In a new book released this month by Jonathan Eig entitled "The Birth of the Pill: How Four Crusaders Reinvented Sex and Launched a Revolution," Sanger is one of the titular revolutionaries who fought to bring contraception into the mainstream.

Of course, she made some powerful enemies along the way. The Catholic Church had long opposed contraception, including the birth control pill, creating a wide rift between church leaders and those in the pews whose bodies and bank accounts were punished by large families.

Sanger, unfortunately, was a far from perfect revolutionary. Her passion for contraception led her into unsavory areas, at times seeming to advocate a style of eugenics.

Critics charged that she and other pro-choice advocates were all-too-willing to abort or otherwise dismiss people who might be defined as “weak” or “undesirable.” Nevertheless, as Eig’s book – and the ongoing debate about Catholics and birth control, which came up yet again at the much-discussed Vatican Family Synod earlier this month – makes clear, Sanger changed the way American woman live.

Which brings us to Margaret’s lesser-known sister, Ethel. Ethel was as passionate an advocate for women’s rights as Margaret. Some even say she was more rebellious than her sister.

Along with Margaret, Ethel opened America’s first birth control clinic in Brownsville, Brooklyn, which landed her in jail. Not one to back down, Ethel went on a hunger strike to garner publicity for what she saw as an unjust imprisonment.

Margaret actually lobbied to get Ethel out of jail, but only on the condition that Ethel steer clear of the law. Not surprisingly, this created a rift between Margaret and the ever-outraged Ethel.

Here’s where things get comic – and kinky. One of Ethel’s daughters was named Olive Byrne. Olive had two children with an academic named William Moulton Marston, who was also a strong advocate for women’s rights.

But that’s not the only thing Marston was passionate about. Because Marston also had children with a woman named Elizabeth Holloway. In fact, Olive, Elizabeth and William all lived together, a mid-century experiment in free love.

This weird, wild story is outlined in a new book entitled "The Secret History of Wonder Woman" by Jill Lepore.

Martson, Lepore notes, was a psychologist who taught at a number of schools. While some folks in the 1930s were worried that comic books were corrupting kids’ minds, Marston defended the industry, a position which landed him a job as a consultant for DC Comics.

While there, he pitched the idea of a female superhero. DC big wigs bought the idea and soon – thanks to the ménage a trios of collaboration among Olive, Elizabeth and William – Wonder Woman was born.

Perhaps the weirdest part of all of this is how the story ends. Marston died in 1947. Elizabeth and Olive continued living together for another 40-plus years.

And the story continues.

A big budget superhero flick featuring Wonder Woman is slated for release from Warner Brothers in 2017.

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