Statistics Canada has just released an interesting study dealing with indebtedness according to family characteristics. While I disagree with the study's premise that indebtedness levels were caused by low interest rates and factors such as "the rise of consumerism" (see here), I thought the sections dealing with the debt profiles of lone-parent families and couple families with children were particularly insightful. According to the study, although the average debt to income ratio in Canada currently stands at 148 percent, the ratios for couple families with children and lone-parent families are as high as 170 percent and 227 percent, respectively. Such statistics are rarely mentioned in most discussions on the issue of indebtedness.
Although the study focuses only on Canadian debt metrics, I can't imagine the situation in other countries with similar demographics (i.e. UK, US or Australia) being any different.