MINNEAPOLIS — A new poll shows the majority of Minnesotans surveyed oppose amending the state Constitution to ban gay marriage.

The Star Tribune Minnesota Poll says 55 percent of respondents oppose such a ban, while 39 percent favor it. Support for the ban seems to rise with age. Sixty percent of respondents aged 18 to 34 oppose the idea. A slimmer majority, 51 percent, of Minnesotans older than 65 oppose the ban.

“We should have our own choices and abilities to choose what we want and not have someone categorize or label people because of their sexual orientation,” said Adam Leistiko, a 22-year-old Democrat from Edina who opposes the marriage amendment. “I have a very open mind.”

The Minnesota Senate approved the amendment this week after lengthy debate. The House is expected to follow suit. If approval is given, voters would be asked in the 2012 election whether the Constitution should be amended to “provide that only a union of one man and one woman” be recognized as marriage. Constitutional amendments need approval from a majority of state lawmakers and a simple majority of those voting in a general election.

The latest survey reflects a change from a Minnesota poll done in 2004 when 58 percent of Minnesotans supported a constitutional amendment limiting marriage to one man and one woman.

Doug Regester, 53, of Minneapolis, said he supports putting the question to voters.

“If there is a way to give the people the say rather than just having a few politicians decide, I’m all for that,” Regester said. Limiting marriage to a union between one man and one woman has been shown “over the centuries” to be “the most beneficial to society,” Regester said.

The poll of 806 Minnesotans was done last week and has a margin of sampling error of plus or minus 4.7 percentage points.