At the start of the midterm election year, Republican candidates hold a slim two-percentage point advantage when voters are asked about their preference for Congress.

Forty-three percent of voters would back the Republican in their House district if the election were held today, while 41 percent would vote for the Democratic candidate, according to the latest Fox News poll.

Click here to read the poll results.

The difference comes from independent voters, who lean toward the Republican candidate over the Democrat by 32-26 percent. Many independents, however, are undecided (28 percent) or would vote for a non-major party candidate (14 percent). Just one voter in five (20 percent) describes themselves as an independent in the poll.

Large majorities of Democrats (84 percent) and Republicans (84 percent) would support their party’s respective candidate.

Views on the generic party vote have shifted back-and-forth in recent months. In October, 45 percent of voters backed the Democratic candidate and 37 percent the Republican. In December it was tied at 43 percent each.

Gay marriage could be a defining issue in some congressional races this year. Nationally, opinion remains split on legalizing same-sex marriage: 47 percent are in favor and 47 percent oppose it. A 55-percent majority of those favoring legalization would back the Democrat in the House, while a 57-percent majority of those opposing legalization would vote for the Republican candidate.

By a three-point margin, more voters now consider themselves “pro-life” (48 percent) than “pro-choice” (45 percent) on abortion. Those views represent a reversal from the last two years when more voters were “pro-choice.” Over half of “pro-life” voters would back the Republican candidate in their district (55 percent). Almost as many “pro-choice” voters would support the Democrat (51 percent).

The new poll also shows 50 percent of voters favor legalizing marijuana, while 43 percent oppose it. Those favoring legalization are more likely to back the Democratic candidate (52 percent), while those opposed would vote for the Republican (57 percent).

Meanwhile, lawmakers generally are still deep in the dumps with voters: 13 percent approve of the job Congress is doing, while 81 percent disapprove. Last month 16 percent approved and 79 percent disapproved.

Congress received a record-low 9 percent approval rating in October 2013.

The Fox News poll is based on landline and cell phone interviews with 1,010 randomly chosen registered voters nationwide and was conducted under the joint direction of Anderson Robbins Research (D) and Shaw & Company Research (R) from January 19-21, 2014. The full poll has a margin of sampling error of plus or minus three percentage points.