Understanding that children's health and development are linked to how well families function, NICHD researchers are trying to better understand the mechanisms underlying family formation and the factors that increase the likelihood that parents can form and maintain a stable family unit. NICHD researchers also evaluate public programs designed to influence family functioning positively, to help policy-makers understand whether such programs are effective.

Earnings, education, and trust help form stable families. New findings in a major study indicate that unmarried parents are more likely to marry each other before their child's first birthday or form a lasting relationship if the father has higher earnings and the mother has graduated from high school. By comparison, couples with less education and income were less likely to stay together to raise their child.[1] The likelihood of forming a stable family is also higher if the mother and father each feel that the other supports the relationship with such behaviors as expressing encouragement and being willing to compromise. Factors that destabilize relationships between new parents include serious health or developmental problems of their child, lower earnings and less education, and a father who has other children with different mothers. These findings can help policy-makers and community programs understand how they can better support fragile families so that parents can provide the stability that fosters the health and development of their children.

Physical or sexual abuse interferes with family formation. In a large study of family formation among low- and middle-income women, researchers found that women who were sexually or physically abused or witnessed abuse as children, or who were physically abused as adults, were less likely to be in lasting marriages or stable relationships, compared with women without a history of abuse.[2] Among the women studied, the researchers found very high rates of abuse, with differing effects on relationships, depending on when the abuse occurred. For example, women whose experience of abuse was in childhood typically engaged in multiple, transitory, and often abusive relationships with men, while women with adult experience of abuse tended to avoid any relationships with men. The researchers suggested that the degree to which abuse interferes with family formation in the U.S. may be substantially underestimated and policies to foster stable homes should attempt directly to reduce the prevalence of abuse.

Experimental program in a developing country improves children's health and school attendance by assisting their families. An experimental Mexican government program (PROGRESA) that tied low-income family assistance to health- and education-seeking behaviors resulted in significantly better health, development, and education of children in families receiving the assistance.[3] A NICHD-supported evaluation of PROGRESA provides insights that could be used in designing interventions for other developing countries and also for disadvantaged U.S. families. In the large, randomized PROGRESA trial, researchers compared two groups of families. In one group, families received substantial financial assistance if they regularly brought their children to health and nutrition clinics, had their infants and toddlers immunized, ensured that their children went to school, and used other specific health and nutritional services. The other group of families did not receive any financial assistance. Researchers found statistically significant health improvements and better school attendance in the children of families receiving the assistance. The effects were stronger, the longer the children and families were in the program.