The number of children being born outside of marriage has increased sharply, according to a new study by the National Marriage Project and the Institute for American Values, CBN News reports. The report focuses on what it calls "middle America," the nearly 60 percent of Americans who complete high school but not college. Among that group, 44 percent of children are now born outside of marriage -- up from 13 percent in the 1980s. "Marriage in middle America is at a tipping point, with unwed childbearing threatening to become a new norm," said study co-author Brad Wilcox. Research shows children born or raised outside of marriage are more likely to suffer from a range of social and emotional problems, including drug use, depression, attempted suicide and dropping out of high school.