Co-Masonry was a natural outgrowth of the feminist suffragette movement of the 1900s. Woman were demanding the right to vote and participate in societies' institutions, and Freemasonry's all male club was considered a hold over from less enlightened times.
The First English exception to the all male rule was Elizabeth St. Leger in 1713, who was detected spying on her Father, First Viscount Doneraile's Lodge in Cork, Ireland. It was thought better to obligate her to the degrees and secrecy. Napoleon followed suit in 1774 in instituting the Rite of Adoption, with matching His and Her Master/ Mistress Chairs. It consisted of Four degrees, Apprentice, Companion, Mistress and Perfect Mistress. Maria Deraismes in France joined an irregular Lodge, Lodge Libres Penseurs aka The Freethinkers Lodge in 1882. She was the first woman initiated in 1800 Europe, and that Lodge was promptly closed by the Grand Lodge of France. Ten years later, Dr. Georges Martin championed the creation of a new, mixed Freemasonry, and La Respectable Loge, Le Droit Humain, Maçonnerie Mixte (Worshipful Lodge, Human Rights, Co-Masonry) was established in Paris, 1893. As it initiated atheists as well as women, few Grand Lodges offered recognition and communication with the new mixed Lodges.
The groundwork was laid by in England and America by such reformers as Susan B. Anthony, Jemima Wilkinson, Dr. Alice Bunker Stockham, Margaret Fuller, Amos Bronson Alcott, Dr. Anna Kingsford, Florence Farr, Edward Carpenter and Madame Blavatsky's Theosophical Society.
In 1900, a schism in the Supreme Masonic Council of France (1879) created more flexibility in the various resulting bodies, all vying for their place in the "Masonic Marketplace". "Le Droit Humain" AKA the International Order of Freemasonry issued a charter and after Spiritual assurances from the "Hidden Adepts" of the Great White Brotherhood, a Lodge of Co-Masons (The Order of Universal Co-Freemasonry in Great Britain and the British Dependencies) opened in London in 1902 under the direction of noted Theosophist Dr. Annie Besant, in cooperation with friend and fellow Theosophist Charles Leadbeater's Liberal Catholic Church. She quickly restored the requirement for belief in a Supreme Being in what was called the "Annie Besant Concord" in 1904.
Influenced by Madame Blavatsky's reliance on Spirit Guides or Hidden Masters, Co-Masonry borrowed from the Martinists, Rosicrucians and Western Occult organizations like the Hermetic Brotherhood of Luxor, Hermetic Order of the Golden Dawn organized around the structure of the old alchemical German Order of the Golden and Rosy Cross common to the Societas Rosicruciana in Anglia (SRIA) and Knights Templar. The revised "Dharma Ritual" (AKA the "Besant-Leadbeater" or "Lauderdale" ritual made more explicit the philosophic teachings inherent in Freemasonry, earning it the nickname of "Occult Freemasonry".
Unlike the Grand Lodge approved Order of the Eastern Star or Tall Cedars of Lebanon, Co-Masonry was independent of the Grand Lodges of the territories in which it became established, and "Communication" has not generally been achieved between them, as has been between the Prince Hall and Blue Lodges in more the half the United States.
Resources: http://en.wikipedia.org/wiki/Le_Droit_Humain; http://en.wikipedia.org/wiki/Co-Freemasonry; Freemasonry by Mark Stavish; Freemasonry: it's history and myths revealed by Giles Morgan, 2009; The Royal Cyclopaedia by Kenneth R. H. Mackenzie;