Apparently, time spent with your young children doesn't matter.
But for teenagers, six hours a week of family time could keep them stable.

Let's look at the results from researchers at the University of Toronto, and Bowling Green State University in Ohio, which tracked 1,600 children above the age of three. The measurement was taken from the actual time spent together, engaged in conversation or not.
The quantity of time parents spent with children aged between three and 11 had no influence on their later academic achievement, behavior and emotional well-being. Not did the hours the mother worked outside the home.
But the research found the total amount of time adolescents spent with their mothers and fathers did have an impact. Just six hours a week made a significant difference to their well-being and achievement, giving lower rates of delinquent behaviour, with less drug and alcohol abuse, and higher academic grades.
A sociologist at the University of Toronto claims that six hours a week, just 50 minutes a day, sharing the same space made a crucial difference. I guess this doesn't mean the teenager can be closed off in their room and the mother in the kitchen.

Let's not discount parent's importance altogether. Plenty of studies have linked quality parent time, such as reading to a child, sharing meals, talking with them or playing games, with positive outcomes for kids. The same is true for parents’ caring and sensitivity toward their children. It’s just that the measure of time doesn’t appear to matter.
Maybe there's nothing special about a mother-child bond after all.
Everything I used to believe has been destroyed by this study. I spent all my time with my children until they left home. I gave my love, care, support, attention, and set a good example. Maybe they saw beneath my calm exterior to the unfulfilled woman inside.
Children are not as naïve as we first assume. They must be able to judge emotions below the surface. The best thing to come from this research is the knowledge that working away from home is acceptable. Release your guilt, mothers of the world.