There was once a time when two groups of people went to war. The Secondary group had no power. They were treated as less than human with no dignity. They had no protection by the same laws that protected the Primary group. In fact, it was the Primary group that decided what laws would protect them and would not protect the Secondary group. The Primary group made all of the decisions for the Secondary group without any regard for the wishes, well-being, or concerns of the Secondary group. The Secondary group had no rights or status and no say in the rules and policies that the Primary group made for them. The war turned ugly. Certain members of the Primary group were concerned that if the Secondary group had the same weapons as them, they would turn their weapons on them and destroy them all (after all, they had it coming after being treated this way for hundreds of years). The tide of war raged on, but at some point the Secondary group was given weapons to fight on the same level as the Primary group, they fought honorably and did not commit the atrocities that the Primary group expected. Eventually, the two groups secured peace and united together under the banner of equality. Members of both groups were given the same power, the same dignity, the same treatment, the same protection of the law, the same rights to set laws, the same ability to enforce them, and the same ability to make their own choices. As a result, their society became healthier, more cohesive, and fairer for everyone.
Now today there's an institution where the Primary group makes all the decisions for the Secondary group and sometimes their bylaws instruct them to ignore the concerns of the Secondary group because it's founding member once said something that lead the founding member of the Primary group astray millennia ago. Much of the lore, tradition, laws, bylaws, rules, teachings, commandments, and history of the institution was written by members of the Primary group, interpreted by members of the primary group, and debated over mostly by members of the Primary group. Any contribution made be members of the Secondary group to the conversation has always been seen as suspect and much of it has been destroyed or labeled as 'incorrect' by members of the Primary group. The Primary group further teaches that it is holy, justice, and right that the Secondary group has a lesser status because of the fault of it's previously mentioned founding member. The Secondary group has no voice because it is written that the sound of their voice is disgraceful. the Secondary group has no representation in the leadership because the rule is that all leaders must be members of the Primary group. Certain members of the Primary are concerned that should members of the Secondary group be allowed to teach, they will usurp the authority of the Primary group and teach things that are not in accordance with the ideas that the Primary group decided is acceptable. The group one belongs to is the one they were born into and that cannot change their status. This arrangement was designed to exist in all cultures, in all countries, and for all time everywhere the institution exists.
When it comes to studying the long-term implications of the Bible, you can draw at least two conclusions: (1.) Jesus ministry serves as an anchor in time, one in which the ideal is firmly rooted in the culture to which he addressed as he taught and challenged the status quo or (2.) Jesus' ministry serves as the source of the trajectory of change, like ripples in a pond, it represents the need of our society to 'move forward' even beyond the specific rules and situations described in the Bible. For most Christians, being Biblical means that they firmly believe that the former is the case. Jesus wants us to reform our world so that it as closely as possible resembles the world the Bible describes. For many, the latter is the truth, in which case Jesus wants us to smooth out the rough edges of the world that he knew to make it a better place.
Which is where slavery comes in. The Bible describes in detail how to have slavery biblically. How to biblically buy slaves, how to biblically be masters, how to biblically settle disputes involving slaves, and how to biblically be slaves and Christians or how to biblically be masters and Christians. The Bible doesn't direct believers to put an end to slavery. But after centuries of slavery, our secular society has written a rule - it is a basic human right to have freedom, therefore forcing people into slavery and owning slaves carries one of the stiffest punishments modern society can agree on. Much of Western society signed the same piece of paper vowing to outlaw slavery. While it does still exist, it's largely an illegal practice that lacks the support of the state and the church. People went to war to win the freedom of people who didn't have power to give them the power they didn't have but should have had all along. But the Bible can't for-see or fathom a world this side of heaven in which slavery (or sexism for that matter) isn't a fact of life. In fact, in Jesus' day, it's estimated that 2/3 of the world - about 60% of the population of the known world - were slaves. Christianity was once called 'a religion of slaves, children, and women'; a faith for people with no freedom, no status, little or no protection under the law. You couldn't find a worse faith to belong to back in the day when power was everything - Christianity was the religion of the powerless.
Somehow we've begun to conquer slavery and racism, but we've neglected to really challenge sexism when it's such a striking parallel particularly in areas of religious belief. The Primary group always needs the Secondary group to believe in it's own inferiority and in the Primary group's superiority. It also needs the Secondary group to believe that they are rightfully subservient to the Primary group on account of that difference. If you can get a subservient Secondary group member to believe in their own subservience, their behavior will comply with all demands that are placed upon them even without the threat of harm for not obeying the rules the Primary group creates for them. They have to believe that if they comply and do their part, then the Primary group will hold up their end of the deal. It exploits trust. When it comes right down to it, "Submission to the will of another is an inappropriate condition to have to satisfy in order to be able to enjoy basic human freedoms."
Christianity has a choice about what statement it wants to make and what beliefs it will teach to the next generations. Christianity used to teach that on account of race, through the curse of Ham, that colored races were secondary and rightfully subservient to the white race. It took another trajectory and decided to move forward. Christianity must answer the same question when it comes to gender. Are women secondary and rightfully subordinate to men? Is that the anchor which must be the foundation of it's beliefs everywhere? Or was it the origin that set the trajectory to move forward and change? Will they continue to teach that women are to submit to men? Will they see to it that women must remain powerless in the church even though the world has begun to make them powerful?
Consider this Read: Overcoming Racism and Sexism by Linda A Bell and David Blumenfeld (particularly chapter 10: Power, Trust, and Evil by Lawrence Mordekhai Thomas)