Currently, only 50 percent of children will reside with their biologic parents until their 18th birthday; therefore, many of the children seen by family physicians live in non-nuclear families. Single-parent families now include more than 18 million children and comprise the most common non-nuclear form of family. The majority of all teen pregnancies result in children being born to single parent homes. It is true that single-parent household's do less well than two-parent households in raising children. 4 pgs, bibliography lists 8 sources.