Pennsylvania, with the largest all-male congressional delegation, could nominate as many as six Democratic women in districts likely to be competitive in November.

All 18 of Pennsylvania’s members of Congress and both its senators are men. So are all five statewide elected government officials.

The state, one of four to hold primary contests on Tuesday, will serve as a test of whether the wave of Democratic women running can dilute one of the country’s most-durable male bastions.

“It’s a breaking of the old style of politics where it was just perceived that it was a man’s world,” said state Rep. Madeleine Dean, the front-runner in a Democratic primary for an open congressional seat in Philadelphia’s Montgomery County suburbs.

All told, Pennsylvania Democrats have 23 women running for House seats. Republicans have just one—Pearl Kim, a former state prosecutor who is unopposed for the GOP nomination in a strongly Democratic Delaware County district.