Many people today would like the traditional two-parent family back--that is to say, they want a man and a woman to marry for life; they also think the man should support the family and the woman should stay home with the children. However, few families now fall into this category. In fact, if more women decide to have children on their own, the single-parent household may become more typical than the traditional family in many countries. Also, unmarried couples may decide to have more children--or they might take in foster children or adopt. And because people are staying single and living longer (often as widows), there may be more one-person households. On the other hand, some people believe similar events happen again and again in history: if this is true, people may go back to the traditional extended or nuclear family of the past. Others think the only certainty in history is change: in other words, the structure of the future family could begin to change faster and faster--and in more and more ways.