If you're a parent, you worry about your children's future. Will they be successful? Will they have good marriages and raise families of their own? Most important of all: Will they have happy lives?

New research from Harvard shows there's one thing you can do that will up your children's chances of having a happy life, decades after they go off on their own, and it's incredibly simple: Be a warm, loving parent.

The Harvard researchers came to this conclusion from an examination of data from the Midlife in the United States study, which examined about 4,000 people in midlife (median age: 47 years, five months) and interviewed them on all sorts of topics. The Harvard team analyzed the data and found a distinct correlation between people who described having warm and loving parents, and people who were doing well in a variety of life areas, collectively known as "flourishing." The concept of flourishing, developed as part of positive psychology, seeks to measure a person's well-being. The study's authors reference this description: "a combination of feeling good and functioning effectively, and the experience that life is going well."

To measure whether a study subject was flourishing, they measured three aspects of well-being--emotional, psychological, and social--by analyzing the data collected on the subjects. They were looking for an association between those who flourished and those who remembered warm, loving parenting, and they found it. Subjects who remembered having warm, loving childhoods were likelier to score higher on the three measures of well-being. Researchers also found that subjects who remembered warm, loving parents were less likely to engage in self-destructive behavior such as smoking or drug use (except for marijuana). What's noteworthy about these findings is that they were collected from people well into middle age. That suggests that a warm, loving childhood confers emotional advantages that are likely to last a lifetime.

The study has some limitations. For one thing, the majority of subjects were Caucasian; they were not representative of the United States population as a whole. (Slightly more than half were female, so the sample was balanced by gender.) Perhaps more significantly, subjects in the study would have been born between 1921 and 1970, which means most grew up before the "helicopter parenting" of today. Would the findings still apply the same way given current parenting norms? Alison Escalante M.D. posed this question when she wrote about the study for Psychology Today. She reports that the Harvard team is at work on new research that should provide some answers.

In the meantime, these findings should provide some relief to parents who worry about preparing their children to have the best possible lives. You may not be able to bribe your child's way into an Ivy League school, provide him or her with every sport there is or otherwise do everything you may think you're supposed to. But you can be warm. You can pay attention. You can show affection. If you do all that, you can help set them up for a lifetime of happiness. And that's what really counts.