Fair or Unfair

Last Sunday I was reading the Austin American Statesman and came across an article that was upsetting. The article recounted the number of children in each state that have died from being left in a hot car. The focus of the article was upsetting as it recounted stories told by parents who left their children in their car. It was, to say the least, very sad.
The part of the article that really upset and angered me, was that woman who leave their children in their car to die, were given harsher sentences than men. Here is the article: http://abcnews.go.com/US/wireStory?id=3424550.
I dont understand why this would be the case. The article seemed to give the impression that a mother leaving a child to die in a hot car is unforgivable while for the father it is tragic. It is a tragedy for everyone.
Do we still have so far to go in equality? Mothers are still seen as the only primary care giver? For a mother to forget or leave her child is seen in judge and jury's eyes to be an act of betrayal. She is the one who cares for that child, how could she do that! Fathers are still seen as having so many things on their minds with work and managing a home life, that this failure is seen as a tragic mistake.
In my opinion both bear the same responsibility. Fathers are stepping up in so many ways in their children's lives. They are no longer sitting by the sidelines but are active participants. This is a good thing. Along with this though comes the same level of responsibility that a mother has daily.