Both economic and interpersonal factors play a role in the likelihood that unwed parents will marry by their child's first birthday, according to an article published in the latest issue of the journal Demography.
"Couples with higher education and earnings were more likely to marry," reported Marcia Carlson of Columbia University , who conducted the analysis with Sara McLanahan of Princeton University and Paula England of Northwestern University.
"The emotional quality of relationships also played a powerful role -- particularly both partners' perception that their relationship was supportive," she said.
The findings are from the five-year ongoing Fragile Families and Child Wellbeing Study, which interviewed about 3,700 unmarried parents at hospitals in 20 U.S. cities shortly after their child's birth. About 3,300 of the couples participated in a follow-up interview about one year later. About 9 percent had married by their child's first birthday.
The researchers found that "supportiveness helps relationships more than conflict hurts them."
In supportive relationships, partners reported that they often encouraged each other, were willing to compromise when they disagreed, expressed affection and avoided insults or criticism. The researchers measured conflict by determining how frequently during the previous month couples reported arguing about money, time together, sex, the pregnancy, drinking or drug use, or infidelity.
They also found that women who trusted men to be sexually faithful were more likely to marry. Couples who believed that marriage was better for children and superior to living together were more likely to marry as well.
Fathers' problems with alcohol or drug use, as well as higher levels of conflict in the relationship, discouraged cohabitation. Physical violence contributed to couples' breaking up.
"Increasing both parents' economic capacities, reducing conflict and violence, addressing substance abuse problems, encouraging positive views of marriage -- and especially promoting supportive behaviors between partners -- could help keep unmarried couples together and encourage marriage," according to the researchers.
At the same time, the researchers note that any policy changes or new programs would likely have only a modest impact on marriage rates.
The researchers also found that the fathers' children by previous partners -- but not the mothers' -- were a strong deterrent to marriage. "This was surprising given that children tend to live with their mothers," said Carlson. "Having other children may keep these fathers from investing in their new children emotionally or financially."
Programs that promote marriage should pay attention to the complicated family dynamics that arise from having children that may be "his, hers or ours," the researchers suggested.
Many of the findings were encouraging, suggesting that a stable family life was possible for some unmarried couples and their children, Carlson said.
Unmarried couples who were living together at the time of the baby's birth were most stable. By the child's first birthday, 75 percent were still living together -- about 15 percent were legally married to each other and 60 percent were still cohabiting.
The research was supported by the National Institute of Child Health and Human Development. Demography is the peer-reviewed journal published by the Population Association of America.