单选题
The last few weeks have brought an unusual convergence of voices from both the centre and the left about a topic that is typically part of conservative rhetorical territory: poverty and single-parent families. Just as some conservatives have started talking seriously about rising inequality and stagnant incomes, some liberals have finally begun to admit that our stubbornly (难以对付地) high rates of poverty and social and economic immobility are closely entwined with the rise of single motherhood. But that's where agreement ends. Consistent with its belief in self-sufficiency, the right wants to see more married-couple families. For the left, widespread single motherhood is a fact of modern life that has to be met with vigorously expanded government support. Liberals point out, correctly, that poverty rates for single-parent households are lower in most other advanced economies, where the welfare state is more generous. That argument ignores a troubling truth: Single-parent families are not the same in the United States as elsewhere. Simply put, unmarried parents here are more likely to enter into parenthood in ways guaranteed to create turmoil in their children's lives. The typical American single mother is younger than her counterpart in other developed nations. She is also more likely to live in a community where single motherhood is the norm rather than an alternative life choice. All of this would be of merely passing interest if it weren't for the evidence that this kind of domestic churn is really bad news for kids. The more 'transitions' experienced by a child—the arrival of a stepparent, a parental boyfriend or girlfriend, or a step- or half sibling (兄弟，姊妹)—the more children are likely to have either emotional or academic problems, or both. Part of the problem is that a nonresident father tends to fade out of his children's lives if there's a new man in his ex's house or if he has children with a new partner. For logistical, emotional and financial reasons, his loyalty to his previous children slackens (变弱) once he has a child with a new girlfriend or wife. Nor is it likely, from the overlooked child's point of view, that a mother's new boyfriend or husband can fill the gap. There's substantial research showing that stepfathers are sometimes worse than none at all.
单选题
Which problem did the conservatives focus on before the debate about single motherhood?