The age at which men and women in America marry is now at historic heights, and as a result the number of children born out of wedlock has also increased, according to a new study by a group of family researchers, who have found that 48 percent of all first births are happening outside of marriage, the Christian Post reports. On average, women are marrying at age 27 and men at 29 -- and the average age is still climbing due to economic and cultural reasons. At the same time, the age at which women have children is also increasing, but not nearly as quickly, according to the report released last week by the National Marriage Project at the University of Virginia and collaborators. For women as a whole, the median age of first birth, 25.7, now falls before the median age of first marriage, 26.5. The report called the phenomenon "The Great Crossover." By age 25, 44 percent of women have given birth, while only 38 percent have married. "The biggest downside to delayed marriage in America is that many young adults are now putting the baby carriage before marriage," said co-author and National Marriage Project director Bradford Wilcox. "What they often don't realize is that children born outside of marriage are significantly more likely to be exposed to a revolving cast of caretakers and the social, emotional and financial fallout associated with family instability and single parenthood."