Is it gender bias (or gender equity?) making Oklahoma #1 in female prisoners?

The question in the title of this post is prompted by this recent story from Tulsa World, which is headlined "Oklahoma leads nation in female incarceration." Here are excerpts:

It’s ironic that the state history of Oklahoma’s female prisoners begins with a reproach to the Kansas penal system. Although corrections officials say that rates of crimes by women and convictions in both states are comparable, today Oklahoma women end up in prison approximately three times as often as women in Kansas.

And while Kansas lawmakers are earning accolades for prison reforms that have reduced prison populations by creating alternatives for some offenders, in Oklahoma, the number of incarcerated women is at a historic high.

Mike Connelly, head of the evaluation and analysis unit at the Oklahoma Department of Corrections, calls it “the hockey-stick look.” That’s the shape of a graph charting the number of women in the state’s prison over the decades, with a long, stable line that suddenly takes a swooping upward turn in the early 1980s.

How sharp?  From 1910 to 1980, women made up an average of 3.5 percent of the state’s prison population. By 2010, that percentage was nearly 11 percent, and the population had climbed to 2,760.

The “hockey-stick” pattern is not unique to Oklahoma’s female prison population, or to the state.  Between 1987 and 2007, the number of prisoners in the U.S. nearly tripled; in 2008, there were more than 2.3 million adults in prison, more by sheer number, as well as per capita rate, than any other country in the world.  The same factors that criminologists point to as having contributed to the growth in prison populations are present in Oklahoma: decades of “tough on crime,” politics, the deinstitutionalization of the mentally ill, the war on drugs and a federally financed prison construction boom.

What the graphs don’t explain, however, is why those factors have operated so severely on women. The nation’s female prison population grew by 832 percent between 1997 and 2007, while the male population grew only half as much.  Nor do they explain why Oklahoma women, in particular, are so much more likely to go to prison.  In 2004, the state imprisoned more than 10 times as many women per capita as Massachusetts or Rhode Island.

Extensive coverage of "Women in Prison" in Oklahoma can be found at this multi-media webpage.