Believe it or not, I think the incidence of women harming their children is actually higher than the father. I honestly haven't the foggiest clue what the motive was, but the fact that she confessed leads me to believe that she felt that she was in her right to do so.
Still, I feel sick looking at the photo of the family. This is sad.
Women, by a wide margin, murder family members or intimates at a rate much higher than men.
See http://www.freerepublic.com/focus/f-news/1602406/posts?page=201#201
Source and stats to back this up.
FMCDH(BITS)