New research shows that over 50% of childbirths for U.S. women under thirty occur outside of marriage. For mothers of all ages, 59% of births take place after wedlock. However, since almost two thirds of children are born to mothers under thirty, the new statistic reveals a surprising trend. In the past, the total number of unmarried childbirths stayed at about 30%. Most unmarried mothers were from poor families. The new numbers show a steep rise in this trend for women who have some college education, but no four year degree.In the U.S., unmarried couples are more than twice as likely to break up as married couples. Still, the fear of divorce is one reason couples choose not to tie the knot. Other reasons are unemployment and low wages for men. Those who do graduate from college largely continue to marry before having kids.