ST. PAUL — A quarter of Minnesota House members wound up voting for their personal preference on legalizing gay marriage rather than following results of last November’s ballot measure to ban it.

Thursday’s 75-59 vote in favor of a bill to permit same-sex marriage saw Republicans and Democrats defy the outcome on the constitutional amendment in their district.

Eighteen Republicans from districts where a majority of voters opposed barring gay marriage voted to keep marriage as exclusively for one man and one woman. Of all the House Republicans who voted against same-sex marriage, Plymouth Rep. Sarah Anderson represents the district with the highest margin against the amendment to prevent gay marriage: Her constituents opposed it by 59 percent to 41 percent.

Gay marriage opponents say a “no” vote on the constitutional amendment wasn’t necessarily endorsement of legalization.

The reverse was true because a “yes” vote last fall was in favor of putting an existing statutory ban on gay marriage into the constitution, a move that proponents hoped would head off any court rulings to strike down the state law.

The amendment lost statewide by a 52-47 margin, but it was the preference in several parts of the state.

Fifteen Democrats bucked the home tide by supporting gay marriage despite representing districts that clearly opposed it. Murdock Rep. Andrew Falk had the starkest difference between his vote Thursday and his district’s vote last fall; nearly two-thirds of voters in his districts wanted the ban on gay marriage.

The gay marriage bill comes to vote Monday in the state Senate, where similar mismatches are also expected to occur.