(CNN) - As the Supreme Court gears up to announce decisions Wednesday on two high-profile cases involving same-sex marriage, a recent poll indicates a growing number of Americans support the right for same-sex couples to legally marry.
According to the CNN/ORC International survey, a majority–55%–of Americans back same-sex marriage, up 11 percentage points from 2008. The same poll indicates 44% oppose the issue.
"In the 1970s, when polls first tackled this touchy topic, a majority of Americans believed that homosexual relationships between consenting adults were morally wrong, a belief that persisted into the 1990s and the first few years of the 21st century," CNN Polling Director Keating Holland said.
"But three years ago, the number who felt that homosexual relationships were morally wrong began to drop below 50%, and currently 54% of the public says that homosexual relationships are not a moral issue. Not surprisingly, that shift in opinion coincided with a growth in support for same-sex marriage," he added.
One of the two Supreme Court cases–Hollingsworth v. Perry–looks at whether the U.S. Constitution's 14th Amendment guarantee of "equal protection" prevents states from defining marriage as being only between one man and one woman.
The case involves California's Proposition 8, a statewide ballot measure that banned same-sex marriages in the Golden State, which California's Supreme Court had previously ruled were legal.
The other case, Windsor v. U.S., examines whether the federal Defense of Marriage Act violates equal protection guarantees in the Fifth Amendment's due process clause as applied to same-sex couples legally married under the laws of their states.
The law known as DOMA defines marriage for federal purposes as a union between a man and woman only.
The case involves Edith "Edie" Windsor, who was forced to assume an estate tax bill much larger than other married couples would have to pay. Because her partner was a woman, the federal government did not recognize the same-sex marriage legally, even though their home state of New York did.
The legal issue is whether the federal government can deny tax, health and pension benefits to same-sex couples in states where they can legally marry.
According to the poll, 60% say the federal government should recognize same-sex marriages performed in states that allow them, with 39% saying they disagree.
The poll was conducted for CNN by ORC International June 11-13, with 1,014 adults nationwide questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.