* Two Republicans among those who voted for gay marriage
* Final results may come down to absentee ballots
* Races watched in states likely to consider gay marriage
By Barbara Goldberg
NEW YORK, Sept 14 (Reuters) - One of three New York state senators who faced tight Republican Party primary elections because they backed same-sex marriage appears to have fended off his challenger, but the results of the other two closely watched contests were still too close to call on Friday.
Senators Mark Grisanti, Roy McDonald and Stephen Saland were among just four New York Senate Republicans to cast crucial votes last year to make New York the most populous U.S. state to allow gay men and lesbians to marry. The fourth Republican senator who backed the measure, which passed the Republican-controlled Senate on a 33-29 vote in June 2011, was not seeking re-election.
According to unofficial results from Thursday's primary elections across the state, voters appear to have stuck with Grisanti but tallies in the challenges to McDonald and Saland were so close that the final result will come down to the absentee ballot count and may not be known for weeks.
The three races were being watched for the strength of the grass-roots backlash against Republican legislators who break with the party's stance opposing same-sex unions. Lawmakers in Rhode Island, Delaware and elsewhere are expected to weigh gay marriage legislation next year and some Republican backing could be needed to pass those measures.
And this November, voters in four states -- Maine, Maryland, Minnesota and Washington -- will decide ballot initiatives on the issue. Gay marriage has been legalized in seven states and the District of Columbia.
After polls closed in Buffalo on primary day on Thursday, Grisanti had a comfortable margin of more than 1,700 votes over challenger Kevin Stocker, a former local prosecutor, according to unofficial results posted on the Erie County Board of Elections website. More than 1,000 absentee ballots that have yet to be opened, according to an election official.
In the Saratoga Springs area, just north of the state capital of Albany, however, McDonald was trailing Saratoga County Clerk Kathy Marchione by about 130 votes, according to tallies posted on county election board websites, and hundreds of absentee ballots are yet to be counted.
In her campaign, Marchione accused McDonald of breaking a promise "to defend traditional marriage."
In another race in the Poughkeepsie area, in the Hudson Valley about 80 miles (130 km) north of New York City, Saland was just 42 votes ahead of Neil Di Carlo, who describes himself on his campaign website as "100 percent pro-family" and said he would repeal same-sex marriage legislation if elected.
Election boards in Dutchess and Putnam counties still must count more than 600 absentee ballots in the race, board representatives said.
Ahead of the primary, gay marriage advocates said the challenges to the three senators were being watched closely as a proxy for testing the momentum of the national drive to legalize gay marriage.
"If all three candidates win it shows that it's safe for candidates and increasingly safe for Republicans to vote for the freedom to marry," said Marc Solomon, national campaign director for Freedom to Marry, an advocacy group for the right of same-sex couples to wed.
If the senators lose, Solomon said, "It won't help."