Slightly more people in Colorado prefer marriage for gay couples over civil unions as the state's civil unions law is about to take effect.

Colorado's law, approved earlier this year on the third try, takes effect on May 1. Civil unions, which parallel many of the same rights as marriage, are also legal in Hawaii, Illinois, New Jersey, Delaware and Rhode Island. Rhode Island lawmakers, however, on Wednesday approved a marriage law, and Illinois and Delaware are considering doing the same.

Colorado voters in 2006 approved a constitutional amendment defining marriage as a heterosexual union, which ties the hands of lawmakers on the issue of marriage until the amendment is repealed.

According to a Public Policy Polling survey of 500 Colorado voters released on Tuesday, 50 percent of Colorado voters support the state's civil unions law, while 38 remain opposed.

But a slightly larger majority, 51 percent, support marriage for gay couples, with 43 percent opposed. Voters under 30 favor marriage by a 74-17 margin.

Seventy-six percent of respondents support either marriage (45%) or civil unions (31%) for gay couples. Twenty-three percent said there should be no legal recognition of a gay couple's relationship.