NICHOLAS RICCARDI, Associated Press

DENVER (AP) — Democrats defending their Senate majority this year are increasingly relying on an issue once seen as a wash with voters: reproductive rights.

U.S. Sen. Mark Udall in Colorado has made it a centerpiece of his campaign to stave off a strong challenge from GOP Rep. Cory Gardner. And from Alaska to Florida, Democrats are highlighting their support for abortion rights to try to drive left-leaning single women to the polls in November.

Republicans say the Democrats are overplaying the point. In Colorado, Gardner has fought back against Udall by disavowing a measure that could grant legal rights to a fertilized egg and advocating for over-the-counter sales of birth control pills.

Nationally, Republicans must gain a net six seats to win control of the Senate.