As the clock ticks toward the Supreme Court's ruling on same-sex marriage, one benefit of equality under the law is often overlooked: health. We know stable relationships and family ties are cornerstones of health, but what does research say about how denying gay and lesbian Americans marriage is also harming their health?

It's a question with somewhat mixed findings, but the bottom line is clear: Broadly speaking, marriage is good for your health.

Not everyone who can get married chooses to, and many who want to still haven't found that certain someone. Someone who hasn't entered into the institution is not necessarily at risk of poor health. Likewise, there are many people in unhappy and unhealthy marriages, so just because you have a license you're not automatically healthier.

Participants carry a rainbow flag during San Francisco’s 42nd annual Gay Pride parade on Sunday, June 24, 2012. (AP Photo/Noah Berger)
Participants carry a rainbow flag during San Francisco's 42nd annual Gay Pride parade on Sunday, June 24, 2012. (AP Photo/Noah Berger)

But married couples who are satisfied with their relationships enjoy better physical and mental health compared with unmarried people. They live longer and are less likely to suffer from long-term illness and disability.

An analysis for the Department of Health and Human Services of dozens of studies found strong correlations between marriage and healthy habits, health care access and use, mental health and longer life.

Marriage reduces drinking and drug use. Marriage reduces health care costs. The happily married are less likely to be depressed, compared with those who are not married. Married people of any age have a lower risk of death.

The federal analysis suggested that mortality rates in any given period are almost 20 percent lower for married people, and a UCLA study of almost 67,000 men and women estimated that the odds of dying in the next decade were 58 percent higher for never-married people.

There's something about being married -- not just being in an intimate relationship -- that has this effect because cohabitating couples don't see the same health benefits as married couples.

Researchers believe it's because married people have guaranteed access to government benefits, rights and privileges -- tax breaks, employee benefits, safety net programs.

The benefits continue even if one spouse dies. A surviving spouse has the automatic right to make funeral arrangements, receive any inheritance and obtain death benefits and bereavement leave. All of these reduce the chances that the death of a spouse will harm the health of the survivor.

What about the children? Children with two parents are less likely to suffer accidents, injuries and poisonings or drop out of school.

Children raised by same-sex couples do as well on measures of mental health and social adjustment as those raised by heterosexual couples.

Research on whether children of unmarried couples are any better or worse off than those raised by married couples is limited. But it stands to reason that if the parents are healthier, stable and better off financially their children will also benefit. The American Academy of Pediatrics agrees.

During the Supreme Court arguments on marriage equality, Justice Anthony Kennedy asked: "There are some 40,000 children in California ... that live with same-sex parents, and they want their parents to have full recognition and full status. The voice of those children is important in this case, don't you think?"

The evidence is compelling that not only their voice is important in the march toward equality, but also their health.

Marnie Purciel-Hill is a research associate with Human Impact Partners in Oakland.