“No Gods, No Masters,” the rallying cry of the Industrial Workers of the World, was her personal and political manifesto. Emma Goldman and Bill Haywood, Mabel Dodge and John Reed, were her earliest mentors and comrades. Allied with labor radicals and bohemians, Margaret Sanger emerged on the American scene in those halcyon days at the turn of the twentieth century when the country seemed wide open with possibility, before world war, revolution and repression provided a more sober reality.

She organized pickets and protests and pageants in the hope of achieving wholesale economic and social justice. But what began as a joyous faith in revolution quickly gave way to a more concrete agenda for social reform. In 1913, working as a visiting nurse on New York City’s Lower East Side, she watched a young patient die tragically from the complications of a then all-too-common illegal abortion, and vowed to abandon palliative work, devoting herself instead to single-minded pursuit of sexual and reproductive freedom for women.

Women would achieve personal freedom by experiencing their sexuality free of consequence, just as men have always done, Sanger predicted. But in taking control of the forces of reproduction, they would also lower birthrates, alter the balance of supply and demand for labor, reduce poverty and thereby achieve the aspirations of workers without the social upheaval of class warfare. Not the dictates of Karl Marx but the refusal of women to bear children indiscriminately would alter the course of history, a proposition ever resonant today, as state socialism becomes an artifact of history while family planning, though still contested by conservative religious forces, endures with palpable consequences worldwide.

In 1917 Sanger went to jail for distributing contraceptive pessaries to immigrant women from a makeshift clinic in a tenement storefront in the Brownsville district of Brooklyn. The nation’s birthrate was already declining as a result of private contraceptive arrangements and a healthy underground trade in condoms, douches and various contraptions, but it was Sanger who first recognized the far-reaching consequences of bringing the issue of reproductive freedom out in the open and claiming it as a woman’s right. She staged her arrest deliberately, to challenge the state’s anachronistic obscenity laws–the legacy of the notorious Anthony Comstock, whose evangelical fervor had captured Victorian politics and led to the adoption by the federal government and the states of broad criminal sanctions on sexual speech and commerce, including all materials related to birth control and abortion. Authorized as a special agent of the US Post Office, with the power to undertake searches and make arrests, Comstock had died of pneumonia two years earlier, after repeated confrontations with Sanger and her supporters that generated widespread publicity and sympathy for her cause, transforming it from a radical local gesture to a cause célèbre.

Appeal of Sanger’s clinic conviction also established a medical exception to New York law. Doctors–though not nurses, as she had hoped–were granted the right to prescribe contraception for health reasons. Under that constraint, Sanger built what became the modern family-planning movement, with independent, free-standing facilities as the model for distribution of services to women without private healthcare, a development that occurred largely in spite of American medical leaders, who remained shy of the subject for many years and did not formally endorse birth control until 1937, well after her clinics had demonstrated its efficacy.

By then, she and Hannah Stone, the medical director of her New York clinic, whom Mary McCarthy later lionized in the classic scene from The Group where Dottie Renfrew gets her first diaphragm, had also achieved a legal breakthrough. They prevailed in a 1936 federal appellate court decision that licensed physicians to import contraceptive materials and use the federal mails for their transport. The ruling effectively realized years of effort to achieve state and federal legislative reform, though it did not override prohibitions that remained on record until the historic 1965 Supreme Court decision Griswold v. Connecticut, which established a constitutional doctrine of privacy to protect the use of birth control, a doctrine extended to abortion eight years later in Roe v. Wade.

Past 80 and confined to a nursing home, Sanger lived to learn of the Court’s ruling in Griswold and to witness the successful marketing of the hormonal birth-control pill she had long dreamed of by a team of scientists and doctors she had encouraged and found the money to support. She died in 1966, just as Lyndon Johnson first incorporated family planning into America’s social welfare programs and committed at least a fraction of the nation’s foreign policy resources to them, fulfilling her singular vision of how to advance opportunity and prosperity, not to speak of human happiness, at home and abroad.

The middle child of a large and poor Victorian family in Corning, New York, Sanger learned to dream at an early age from a magnetic Irish father who squandered away his artisan talents and his humane social vision on far too much talk and drink. From an overburdened but resourceful mother and several older sisters, however, she was lucky to absorb a powerful motivation to improve her own lot and the essential habits of self-discipline that made it possible to do so. One parent taught her to defy, the other to comport. She always warred between the two but took away from both a distinctive resolve to invest in a better life for herself and for others.

Never one to romanticize the poverty of her youth, she took refuge as a young teenager in Catholicism, then quickly converted to a socialist catechism, jettisoning both after World War I in favor of a more reasoned confidence in the ability of science and education to shape human conduct and in the possibility of reform through bold and progressive public initiatives. Her mentor through this passage was no less than H.G. Wells, the renowned British man of letters and influence, who foresaw the development of states that would mix free markets with centralized planning for social welfare. Both became tribunes for the rational, scientific control of the world’s population and its resources, with Wells giving Sanger entree to the League of Nations and enhancing her international stature.

The two shared reputations for thinking expansively about the future, but also for living brazenly in the present. Sanger left her first marriage to William Sanger, a fledgling architect and painter, and committed herself to free love. Wells was one among many liaisons during and after her second marriage of convenience to J. Noah Slee, the wealthy inventor of 3-IN-ONE household oil, who used his facilities to help her smuggle in contraceptive products from Europe before they were legal here and helped bankroll her efforts, all the while letting her work, travel and have her freedom.

Critical to Sanger’s political transformation at this juncture was the maturing of her consciousness as a feminist. She lost confidence in the potential of class cohesion, but decided to invest in the collective potential of women, many of whom were oriented to activism by the suffrage movement and eager for a new cause after women finally won the vote in 1920.

Openly rebelling against conventional gender arrangements, Sanger insisted nonetheless that the price women pay for equality should not be their sexuality or personal fulfillment. Following in the footsteps of a generation of suffragists and social do-gooders who had proudly forgone marriage, she became the standard-bearer of a less ascetic breed, intent on a broader range of satisfactions. She wanted women to have it all, and saw birth control as the necessary condition for the resolution of their often conflicting needs.

Sanger’s determined optimism about the possibilities of freeing sex from a culturally and religiously enforced shroud of mystery and myth made her a pioneer of modern sexology and one of the first to take advantage of the popular market for lovemaking textbooks that emerged in the 1920s and ’30s. An intimate disciple of Havelock Ellis, and a fervent opponent of the confining determinism of Sigmund Freud, she believed that improved communication and instruction in technique has the power to liberate human sexuality even from the yoke of the unconscious.

In no small measure, her success in this regard owed not just to the weight of her ideas but also to her considerable personal beauty and charm. She was an immensely attractive woman, small, lithe and trim. Her green eyes were flecked with amber, her smile always warm, her hands perpetually in motion, beckoning even to strangers. By Wells’s own testimony, she had a quick Irish wit, high spirits and radiant common sense. And she was, in his words, “genuinely pagan.”

With an uncanny feel for the power of a well-communicated idea in a democracy, Sanger through the 1920s wrote bestselling books, published a widely read journal, held conferences, circled the globe giving lectures, organized a network of clinics and built a thriving advocacy movement. To this end, she had no choice but to mobilize men of influence in business, government, labor, academia, science and the emerging professions, but her most active recruits always remained women. Under the best circumstances her pioneering clinics provided a range of health and counseling services in a sympathetic environment and became laboratories for her idealism, but, as often as not, the experiments failed, and even Sanger herself grew disillusioned.

The birth-control movement stalled during the long years of the Depression and World War II, stymied by the cost and complexity of reaching those in need without public funding, engulfed by internal dissension and overwhelmed by a barrage of opposition. The ever-fragile alliance Sanger tried to forge with the country’s social and business establishment became a distinct liability. She resigned from the American Birth Control League, which later became Planned Parenthood, because of the eugenics leanings of some of its leaders, who boldly advanced contraception as a means of slowing birthrates among the poor during the Depression. Eugenics, which addresses the manner in which biological as well as environmental factors affect human health, intelligence and opportunity, was once embraced enthusiastically by many on the left but quickly deteriorated into excuses for the sterilization and control of “undesirables” on the basis of race and class.

Sanger always disdained the idea of a “cradle competition” between rich and poor, native and immigrant, white and black. She preached an ethic of individual self-improvement that would “come from within.” She advanced public health and welfare policies fostering universal health and fitness and providing essential economic safety nets, and she spoke out against immigration prohibitions and other stereotypes. Having worked as a midwife, she was particularly sensitive to the adverse biological consequences of inadequate nutrition and healthcare for pregnant women.

But by bemoaning the burden of the “unfit” and by joining other progressives in refusing to condemn involuntary sterilizations of the institutionalized, Sanger left herself vulnerable to attacks of bigotry. Her reputation has been seriously compromised in recent years by an unlikely alliance of opponents of abortion on the far right and those on the far left who wholly reject her pragmatic political strategies, or condemn all family planning as covert ethnic and racial genocide.

Undermining Sanger’s character as a way of undermining her message has long been an effective political strategy. Though she had enjoyed the personal friendship and professional endorsement of Franklin and Eleanor Roosevelt in New York, they refused to publicly ally themselves with her self-consciously transformed and sanitized “family planning” message when they reached Washington and became captive to the New Deal’s dependence on an alliance of Catholic voters in the Northern cities and fundamentalist Protestants in the rural South.

Embittered by her failure to win support at home, and disenchanted with the country’s increasing pronatalism after years of deferred fertility during the Depression and World War II, Sanger grew increasingly irritable, conservative and rabidly anti-Catholic as she grew older. Having previously traveled to Japan, China and India, leaving rudimentary family-planning advocacy and service organizations in her wake, she again turned her attentions abroad. In 1952 she founded the International Planned Parenthood Federation, an umbrella for national associations that remain today in most countries. In recent years most of these groups have been reinvigorated by a feminist movement that has given resonance to Sanger’s original claim that women have a fundamental right to control their own bodies. They are recommitted to a doctrine that once again weds population and development goals to improvements in women’s status.