A recent study found that in the 20 years since Massachusetts became the first state in the U.S. to grant same-sex marriage licenses, same-sex marriage has strengthened the institution of marriage for all couples and improved benefits to children.

Rand, a social policy organization, reviewed 96 studies conducted over the 20-year period since Massachusetts began granting same-sex marriage licenses on May 17, 2004. The researchers found the opposite of what conservatives claimed when opposing same-sex marriage in the decades prior to the U.S. Supreme Court decision, Obergefell v. Hodges, which granted the right to same-sex marriage nationwide. Instead of ill-effects on the institution of marriage, Rand researchers found that the lack of prohibition led to an increase of marriage for difference-sex partners as well as same-sex partners.

New Mexico began granting same-sex marriage licenses in 2014.

The researchers also did not find an increase of cohabitation of either same-sex or different-sex partners, as conservatives once feared. Rand also did not find a consistent change in divorce rates. But they found that since legalization for same-sex couples, young people’s attitudes toward the institution has improved.

Marshall Martinez, executive director of Equality New Mexico, said he was not surprised by the findings. 

He said he thought that before marriage equality, the average straight person was not concerned with prohibiting same-sex couples from marrying and that the fight over marriage equality was a battle with the far right. 

“They were blowing out of proportion that what we were out to do was to ruin whatever their view of marriage is,” he said. “How many thought marriage had to mean what the church thought it was?”

Martinez said the fact that marriage equality has been a national right since 2015, when the Supreme Court ruled on Obergefell v. Hodges, has meant that it’s much easier now for same-sex married partners to be recognized in a hospital without the partner in the waiting room having to bring in documentation to prove the couple are married.

Martinez said he has seen, first-hand, different-sex couples claim they are married in a hospital waiting room and the staff do not question the couple’s status, as they might question a same-sex couple. 

“I would watch and think I know queer couples who had to get powers of attorney to get a basic update from a doctor after surgery,” he said. 

Advocates often point to being able to make decisions for a loved one or even being able to visit a loved one in a hospital as a primary reason why marriage equality is so important.

Martinez said another reason is because the U.S. lacks universal health insurance. Being able to marry one’s partner can mean both partners can be on one partner’s health insurance. Although Martinez said that since gay rights activists in the early years of the HIV/AIDS crisis highlighted the importance of universal healthcare, he found the findings of increased health insurance for same-sex couples “bitter sweet.”

“I’m so grateful for folks who are able to access health insurance because they got married to somebody but it’s also really infuriating. Queer folks were at the forefront of the movement so long ago. The best we could get was to marry someone to get insurance,” he said.

But Martinez said the problem that ensues when one partner lacks good benefits while the other partner, who happens to have a job that provides such, has good benefits is one that resonates for the average American. 

The Rand research found that, overall, since marriage equality, same-sex couples have reported lower stress, greater positive mood and fewer depressive symptoms, in addition to higher levels of health care, higher levels of health insurance coverage, and declining rates of sexually transmitted disease and substance abuse disorders.

Martinez said the American Heart Association’s findings a few years ago showing that individuals within the LGBTQ community have higher rates of poor cardiac health came to mind when he looked at the Rand findings. 

Related: AHA: LGBTQ at greater risk for cardiovascular events and risks

“Just the benefit of marriage in terms of health outcomes starts with, you have this partner: The government, the hospital, supervisors at work cannot ignore or undermine because the law exists. You have a base level of acceptance of respect for who you are and that immediately mitigates stress and trauma,” he said.

The study also found benefits to children since the beginning of marriage equality. Disparities in academic progress between children of same-sex couples and children of different-sex couples have reduced. Health insurance benefits for children of same-sex couples also improved. When states began legalizing same-sex marriage 20 years ago, same-sex couples within those states experienced higher earnings, more stable relationships and a higher rate of homeownership, the study found.

Martinez said the Supreme Court’s marriage equality ruling was “a very clear message.”

“You are deserving of a life of happiness and sustainability that includes marrying the partner of your choice. You get to have your fantasies about that. Lots of little lesbian girls and gay boys got to dream about their wedding dress for the first time. That is a classic American experience as a child,” he said. 

Martinez said that one reason why the findings that same-sex marriage has improved the institution of marriage even for different-sex couples didn’t surprise him was because of research EQNM did a few years ago in New Mexico. They found that 73 percent of New Mexicans said in the poll that they have a close, personal relationship with someone who identifies as LGBTQ. 

“The vitriol we saw from conservatives regularly bringing up marriage equality had a harmful impact on straight folks. Those were our nieces and cousins who were being vilified in the press for the audacity of wanting what their parents had,” he said.