"There is also a noted gender bias: Mothers are more often charged than fathers, and among the convicted, women caregivers receive longer prison sentences than men, the study found."
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I am not sure what study the author is referring to.  They reference the Kids and Cars organization so one possibility is: 
http://www.kidsandcars.org/files/2014/08/2006-heat-crime-and-parenthood.pdf
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From my reading of the article the major bias is between prosecution of third parties and the parents.
Better reporting would have included this.
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The reported conviction rate for mother's was 92% versus 90% for men.  
68% of the women got jail time and 55% of the men.
As for the jail time discrepancy, the reporter's jump-to-conclusions is gender bias.  Another possibility is that the mother's crime was often worse.