Women in Freemasonry: The Material Aspect

Regular Lodges of Freemasons such as the United Grand Lodge of England have made it clear that Freemasons are free to explain that yes, women are accepted as Freemasons. However, this is something of a foil, as there is no formally recognized Lodge accepting women. There are two such fully female Lodges in England (The Order of Women Freemasons and The Honourable Fraternity of Ancient Freemasons) which are admittedly regular in every aspect except that they are female, but they are not even allowed formal contact with regular male Lodges. Of course, there are Orders such as that of the Eastern Star, but these are considered by traditional, male Lodges as simply mirroring Freemasonry and not as equals. So why, considering that Freemasonry has changed a good deal since its inceptions in the twelfth century, are women still not considered as equals?

First off, every Freemason must swear in his obligations to never help in the making of a woman into a Mason. Some men consider this to be too powerfully binding and unchangeable to overcome, whatever their personal beliefs.
Secondly, Freemasonry is a fraternity. If there exist side by side female organizations, why should the men include the women, since they have their own possibilities?

Perhaps most importantly, mainstream Masonic bodies follow the regulations laid down during the 17th century, one of which is the strict exclusion of women.

I'm interested in further exploring the reasons for excluding women, in addition to finding things that have changed in mainstream Freemasonry which might necessarily have been considered quite as strange as introducing women. I'll also be researching current opinions of important figures in modern Freemasonry.