Gay, lesbian and bisexual couples seeking senior housing receive less favorable quotes on pricing, availability, and amenities than heterosexual couples, according to a report released Wednesday by the Equal Rights Center in Washington.

In a model similar to studies involving people of different racial and ethnic origins, testers posing last year as members of straight or gay couples in their 60s and 70s called age-restricted housing facilities in 10 states to inquire about living there. According to the report, “Opening Doors: An Investigation of Barriers to Senior Housing for Same-Sex Couples,” in 48 percent of the 200 tests, the LGB tester with a same-sex spouse encountered at least one type of adverse differential treatment compared with the heterosexual tester with an opposite-sex spouse.

The discrimination included heterosexual testers being quoted lower rates for rents, deposits, and fees or being told about the availability of more units than LGB testers were told about. The LGB testers were also offered fewer incentives to rent and were presented with more application requirements or were steered away from the units they had requested, even though members of this group presented a slightly better financial profile than the heterosexual “couples” matched with them.

In some states, the level of discrimination correlated strongly with whether the state has enacted legislation against same-sex discrimination. For example, in Arizona, which has no such legislation and does not recognize same-sex marriages, 80 percent of LGB testers experienced at least one kind of adverse treatment, and 15 percent experienced more than one form. In Washington state, which prohibits discrimination in housing based on sexual orientation and does recognize same-sex marriage, 30 percent of LGB testers experienced at least one kind of adverse treatment and 5 percent experienced more than one form.

Elsewhere, the presence or absence of protective laws made less of a difference. In both Pennsylvania, which has no protective legislation, and New Jersey, which does, 40 percent of LGB testers reported adverse treatment.

To help end such discrimination, the report recommended that the Fair Housing Act be amended to include sexual orientation and gender identity as protected classes and that enforcement of existing laws be improved. It also called for senior housing providers to adopt anti-discrimination policies and increase awareness and sensitivity training related to lesbian, gay, bisexual and transgender seniors.

“Existing laws need to be enforced, because there is a lot of this problem even where protections exist,” said Don Kahl, executive director of the Equal Rights Center, which undertook the study in partnership with Services and Advocacy for GLBT Elders, an advocacy group for older LGBT people.

Kahl said the study is “a really good tool to show policymakers and legislators that this is an issue that needs to be addressed.”

A similar pilot study conducted by the center in 2011 and 2012 in the Washington metro area found that in Maryland, which has protective legislation and recognizes same-sex marriage, 46 percent of testers seeking housing for a same-sex couple reported at least one form of discrimination, while in Virginia, which has no such protection or recognition, 58 percent of testers reported it. The number of tests in the District was too small to draw any significant conclusions.

There is no reliable count of older LGBT people in the United States. The Institute for Multigenerational Health at the University of Washington estimates that 2 million Americans 50 or older identify as LGBT, with that number expected to double by 2030. The National Gay and Lesbian Task Force estimates the current number of LGBT people 65 and over to be 3 million, with 6 million projected by 2030, according to the study.

About 15,000 people over age 50 who identify as LGBT are estimated to live in the Washington metropolitan region, according to the University of Washington institute.

Many older Americans came of age at a time where strong stigmas against same-sex couples largely kept LGBT people from being open about their sexuality. Doctors classified homosexuality as a disorder and states did not begin offering legal protections until the 1980s.

Older LGBT people are four times less likely to have children and grandchildren and twice as likely to live alone as their straight counterparts, according to the National Gay and Lesbian Task Force Policy Institute. Because of this, and because many lost close friends in the AIDS crisis, they often find themselves more isolated than heterosexual people as they age.

A 2011 survey by six LGBT and older-adult advocacy groups found that just 22 percent of LGBT aging adults felt they could be open about their sexual identity in a nursing home or assisted-living facility, and many feared discrimination.

Discrimination based on sexual orientation and gender identity has been prohibited in all HUD-funded or -subsidized housing since 2012, but the prohibition applies only to lower-income housing.

The report’s findings did not surprise Patrick Paschall, senior policy counsel for the National Gay and Lesbian Task Force, who noted that discrimination has a disproportionate impact on LGBT people throughout their lifetime, resulting in lower incomes and fewer housing options.

“State and local government should take an active role in preventing discrimination . . . so that LGBT seniors can feel safe as they search for senior housing, knowing that they have legal protections in the place where they live,” he said.