Christianity has always held that sin lies in the will. If Eve really was decieved enough not to realize her acts were wrong, then they were not sin. Adam has no such excuse. He very clearly willed to do wrong with no doubts that it was wrong. His guilt is greater than hers. The book of Romans says that Sin entered from one man, Adam, and does not mention Eve much lest try to place most of the blame on her.
Blaming Eve, and women in general, seems to have started with Tertullian. He had a huge impact on the western church (mostly though his influence on other Berber fathers such as Augustine), but was always considered a fanatic and was eventually declared a heretic.
I think too there was a certain need for early Christianity to wrestle people away from the Pagan religions which tended to worship the goddess. There are many things that Christianity stole from earlier religions, even as far as to build churches on pagan sacred sites and such. I am convinced taht the devil symbology is directly related to Celtic worship of the Horned God. Another thing was that these pagan religions tended to have a deep reverence for the "mother" or "goddess" and women had roles of power.
The common depiction of the devil was explicitly made in order to discourage the worship of Pan, who was a very popular deity among the inhabitants of rural villages. (Pagan comes from the Latin Pagani, which literally means "the village people.") Pan was sometimes synchronized with the Celtic Horned One, but has a seperate origin.
In the early years of the church, demons were not depicted as giant powerful monsters, but as small annoying insects like gnats or mosquitoes. They were thought to be unable to force anyone to do anything, only to suggest thoughts to the mind through the body. They were not considered spirits like angels, but somewhat ethereal yet still physical beings who could not influence the soul directly. Even if they could take control, they could never make anyone sin, as sin is by definition and act of the will which must be freely chosen.
Although the masculine pronoun was the norm, God is not traditionally considered to have a gender. A few biblical names of God are grammatically feminine. The name often translated as "almighty" is more likely to mean "my teat." The Koran makes of point of randomly changing the gender of the pronouns used for God to emphasize he is beyond male or female.
Celtic paganism may have been relatively pro female, but Greek and Roman paganism were very misogynistic. Sure, there were a few special priesthoods for women, but in general women were considered to be incomplete men, their gender considered almost a birth defect. Christianity offered a then unprecedented level of equality to many women. In the first few centuries women formed a significant majority of Church. There are women in the new testament that where significant leaders in the church.
The church also put an end to rampant witch trials. Far more witches were executed by pagans than christians. In the middle ages the church's official position was that witchcraft was not real; only God had supernatural powers, and those claiming otherwise were just charlatans using cheap tricks. Witch trials didn't become common until the protestant revolution, and never reached the levels of antiquity.
