Are juries more sympathetic to male or female criminal defendants/victims?

Psychologists at Penn State surveyed 458 people about how they'd vote if they were on a jury in a hypothetical case where a defendant was accused of killing his/her lover "in the heat of passion" after being thrown out of their house and discovering that the lover was cheating. The researchers described the case with 4 different possible gender configurations: male defendant/female victim, female defendant/male victim, both male, and both female. Miller-McCune reports:

Test participants were given “jury instructions” stating the defendant was charged with second-degree murder. They were given the option of convicting the defendant on that charge, going with a less-serious charge of voluntary or involuntary manslaughter, or finding the defendant not guilty by reason of insanity.

To parse out levels of ambivalence, the researchers asked participants to rank, on a 1-to-7 scale, the extent to which they find the defendant guilty. They were also asked to choose an appropriate sentence length, from no prison time to 15 or more years behind bars. . . .

Heterosexual female defendants were given significantly shorter sentence lengths than either heterosexual male defendants or homosexual defendants. They also scored lower than any other group on the question “To what extent do you find the defendant guilty?” And they scored the highest in terms of satisfying specific legal elements that would justify a voluntary manslaughter verdict, such as great provocation and mitigating circumstances.

“The findings from this study suggest heterosexual female defendants are more likely to benefit from using the provocation doctrine in a crime-of-passion case,” the researchers conclude. While straight women appear to be “just as likely to be convicted as all other defendants,” their punishment — at least to the extent it is determined by the jury — is apt to be less severe.

These findings seem to corroborate the conclusions of University of New Hampshire sociologist Murray Straus, who has argued domestic violence is often looked at as less serious if it is perpetrated by a woman. Specifically, Ragatz and Russell found that “violence perpetrated by heterosexual female defendants toward their unfaithful partner was perceived as more acceptable than violence perpetrated by male or homosexual defendants.”

The study can also be interpreted to support . . . the notion that defendants receive harsher sentences when the victim of a crime is female. The researchers noted that “both heterosexual male and homosexual female defendants were found more culpable if the victim was female. Whether the female victim was heterosexual or homosexual did not appear to impact decisions.”

Either way, the results suggest gender-related beliefs play a major role in jurors’ decision-making processes.

Why is there so much less interest in the criminal justice system's possible gender bias than in its possible racial bias?