Answer:
The answer to the questions: According to research, what are people´s general thoughts on family in the United States, How do they view non-traditional family structures? And, How do you think these views might change in twenty years?, are pretty complext.
In the first case, research as of 2010 and later, shows that although most Americans still consider that a family is defined as a group of people who share a relation, be it through marriage, blood, or adoption, and who mostly cohabit, and who are grouped as: husband, wife and children, mostly, these views have been changing. The key factor now seems to be whether a couple has children or not, and the kind of committment that exists between them. But Americans seem to still favor, as much as 98% of those surveyed, the traditional concept of family. They are slowly accepting the existence of homosexual families, and single-parent families, but these are not as accepted as it would be thought for a country that predicates on equality.
On the second question, research also shows that Americans are slowly, but surely, comming to accept the presence of nontraditional family structures, even if they do not necessarily have changed their view on what a family should be like. According to statistical data, at least above 50% of Americans already accept the existence of homosexual families, homosexual couples without children, single-parent family groups and composite family groups.
I believe that the change from here to 20 years will be significant, as people become more open to the fact that things will not go back to the way they used to be. The advance of LGBT lobbying for equal rights and recognition, and the dissolution of so many traditional views, things will change even further from what they were 50, or a 100, years ago.