A study by Sonja Starr, an assistant law professor at the University of Michigan found that within the United States’ justice system, women generally receive much more lenient treatment over the same crimes.

This study finds dramatic unexplained gender gaps in federal criminal cases. Conditional on arrest offense, criminal history, and other pre-charge observables, men receive 63% longer sentences on average than women do. Women are also significantly likelier to avoid charges and convictions, and twice as likely to avoid incarceration if convicted. There are large unexplained gaps across the sentence distribution, and across a wide variety of specifications, subsamples, and estimation strategies. The data cannot disentangle all possible causes of these gaps, but they do suggest that certain factors (such as childcare and offense roles) are partial but not complete explanations, even combined.

Other research has confirmed Starr’s findings. Jill K Donner stated in her report, Explaining the Gender Gap in Sentencing Outcomes: An Investigation of Differential Treatment in U.S. Federal Courts

Overall, the findings of the current study are consistent with those of past research on gender and sentencing in dictating that female defendants are sentenced to less severe sentence outcomes than similarly situated male defendants, even after controlling for legal, extralegal, and contextual factors. In addition, the current study found that gender weighed differently across offense type, type of sentencing departure, and racial/ethnic category. Also, extralegal factors were found to influence defendants differently when the sample was partitioned into individual gender groups.

In the course of investigating explanations previously offered to justify the disparity, Starr found that even combined, the factors described couldn’t account for the majority of the difference. She noted that the most prevalent arguments weren’t solid, and even treating them as such, each only accounted for small percentages of cases, and each had exclusions.

She looked at criminal reports, including the use of specific criminal codes and officer descriptions. Her research showed that unobserved differences in severity, while not completely ruled out, aren’t supported by evidence as a major cause for the disparity.

She found that criminal history, attitude, and cooperativeness couldn’t explain the gap, citing a 2004 study which found that “other factors equal, reported crimes with female offenders are substantially less likely to lead to arrests, results that they interpret to show police leniency toward women.”

Challenges to culpability on the basis that women were charged as accessories to male crimes also couldn’t explain away a significant portion of the gap, and Starr noted that the “girlfriend argument” explains nothing about single-perpetrator crimes.

Looking into the argument of family hardship, she found evidence of gender-discrimination that favors women, and harms men.

In short, the family status-gender interaction appears to be more substantial than the one formal legal mechanism for accommodating family hardship can explain. Prosecutors and/or judges seem to use their discretion to accommodate family circumstances in sub rosa ways—but not for male defendants. Among single men, conditional on observables, having children significantly increases sentences, and among married men, children make no significant difference.

She also looked at arguments citing life circumstances such as addiction, mental illness, or abusive environments.

Together, all such cited bases for departures explain only between 1 and 2% of the otherwise-unexplained gap in sentence length; they are too rare too explain more. If prosecutors or judges take such factors into account in informal ways (as they seem to with family hardship, above), it would be unobservable.

If factors related to crimes and their perpetrators are not the main causes of the gender gap in sentencing, why does it exist? One clue to this is in Starr’s explanation for differences between her study, and studies which showed a narrower gap. She wrote in her report that previous studies may not have shown such a sharp difference because they had not looked at the role of plea bargains and other pre-sentencing steps in the criminal justice system. The difference this makes is in the role of prosecutorial influence.

The United States in effect has a system of negotiated justice, and prosecutors hold most of the chips. They have broad discretion to choose charges from numerous overlapping criminal statutes, and then to determine the terms of plea deals. Plea-bargaining does not necessarily focus mainly on dropping of charges—indeed, the lead charge was dropped only 17% of the time in this study’s sample. The parties also often negotiate stipulations to key “sentencing facts”—for instance, the quantity of drugs trafficked or the defendant’s major or minor role in a conspiracy. The prosecutor also may make non-binding sentencing recommendations or request special leniency to reward cooperators.

She also points out that prosecutors’ gender bias can stem from the importance of public relations.

Prosecutors have a variety of incentives to balance, including career incentives that push toward maximizing sentences and resource constraints that discourage going to trial (see, for example, Baker and Mezzetti 2001; Easterbrook 1983). In addition, prosecutors may be affected by sympathy or a sense of fairness. Schulhofer and Nagel (1997) review federal prosecutors’ case files and find evidence of deliberate charge manipulation to avoid excessive sentences. Prosecutorial discretion is often described as the power not to seek to maximize punishment—to be selectively lenient (see Stith 2008). Although there may be good policy reasons for allowing such discretion, it is a potential source of unwarranted disparity if it is influenced by legally irrelevant factors such as gender.

To put it simply, putting a woman on trial can be a public relations nightmare for a prosecutor, who is faced with a defendant who may damsel for both jury and public sympathy, painting herself as a victim of prosecutorial bullying. Not only can prosecuting a vulnerable seeming woman backfire by leading to acquittal due to sympathy, it can also come back to haunt the prosecutor during an election.

Why would only prosecuting female criminals create bad PR and not male criminals? Doesn’t the public want to be protected regardless of with whom the criminal activity originates?

That depends on which public you’re asking.

The National Organization for Women has actively promoted some of the myths surrounding gender disparity in sentencing, as shown in in this summer 2001 blog post about population increases in women’s prisons. The article mixes description of real issues (prison rape) with claims that women commit crimes only as accessories to male criminals, and uses an anecdotal description to suggest that female criminal behavior is a result of abuse by a man. The article goes on to lament that incarceration separates mothers from their children, a concern NOW hasn’t shown for imprisoned fathers in their advocacy for increases in prosecution of men unable to keep up with child support obligations, and against shared custody proposals made by fathers’ rights groups. Feminist logic: female drug dealers are good and valuable parents, but fathers are disposable… except for their wallets.

Guidelines handed down in the UK in 2010 admonished judges to go easier on female offenders. In 2011 a UK Women’s Justice Task Force report offered the suggestion that women’s prisons in the UK be replaced with community service and mental health treatment. While the research done by the group making the suggestion is of interest, there is nothing in it to suggest that it is applicable only to women… yet the suggestion has not been extended to apply to male offenders.

In contrast, feminist activism in the U.S. led to the enactment of the Violence Against Women act, a law written to address a gender-neutral problem as if women were the only victims, and men the only perpetrators. VAWA contains federal financial incentives for policies to promote mandatory arrest, prosecution, conviction, sentencing, and sentence enforcement. The same group that thinks punitive imprisonment for female offenders is unfair and cruel has no problem with a law that incentivize false accusations against men, and places them at risk for wrongful conviction and false imprisonment.

Feminists claim that an anti-discrimination clause added in 2012 makes the law gender-neutral despite its overwhelming prevalence of female-specific language for victims, and male-specific language for perpetrators. However, from 1994 through 2012, the wording and the law’s enforcement followed a male-perpetrator, female victim model that led to greatly increased arrests and incarceration of men without demonstrably affecting the prevalence of partner violence in the United States. In addition, the theory that the non-discrimination clause applies to enforcement and not just services has yet to be demonstrated.

If, as feminists argue, harsh, long sentences for men are right because the point of the penal system is to protect the public by deterring would-be criminals and containing those who are not deterred, what does the gender disparity say about female criminals and their victims?

Are experiences of crime victims less important if their perpetrators are women?

Does society think women less possessed of the self-control necessary to keep their behavior within the bounds of the law? Isn’t women having less culpability an indication of less capability?

If that’s what it means, but it isn’t right, why aren’t feminists actively lobbying for reform? Where is the letter-writing campaign demanding more lenient handling of male criminals, or more harsh handling of female criminals? Where is the massive, heavily attended perp-walk to protest unequal treatment by law enforcement, prosecutors, judges, and juries?

Given that feminist advocates have argued for lenient treatment for female convicts, it’s unlikely that they’ll also advocate that all convicts should be treated equally if it means women would face the same heavy sentences as men.

If, as feminists argue, harsh, long sentences for women are wrong because they’re cruel punishment that is undeserved and doesn’t achieve rehabilitation, what does this gender disparity say about the way we treat male criminals?

Are they less valuable than women… so much that society can accept treating them like trash when women who do the same things are considered redeemable?

Is it that men are considered so much smarter, more reliable, and generally better than women that society must hold them to a higher standard, and require greater retribution when they fall from it?

If criminal sentencing is a human rights issue when dealing with female convicts, why can’t the same be recognized when the convicts are men?

Are some humans more human than others?