The pro-choice group CREDO Action is circulating a petition to stop a congressional investigation of Planned Parenthood.
The Hill newspaper reports the group has secured 130,000 signatures against the probe.
"Anti-choice members of Congress are using this investigation to launch yet another attack on Planned Parenthood," Becky Bond, political director of CREDO Action, said.
"If they can't defund the organization, they want to tie up its staff and resources in a politically motivated investigation," she added. "This is an unfair and unjust political assault, and we can't let them win."
Rep. Cliff Stearns, R-Fla., has requested information from Planned Parenthood on its finances and policies for obeying federal laws.
He said Planned Parenthood is given almost $360 million a year from the government, and wants the group to be held accountable if it's used the funds for abortions.
"Really our investigation is to see how this money is being used, to try and track it and a larger sense to say, 'Here we are broke in the country and should we be giving that amount of money to Planned Parenthood,' especially in light of their misconduct," Stearns said Thursday on "The 700 Club."
Stearns also commended groups like Americans United for Life and the Live Action Network for exposing some of the bad behavior taking place in Planned Parenthood clinics.
Most recently, workers were caught on tape saying women on Medicaid could get the same check-ups they received at Planned Parenthood elsewhere.
That's contrary to what Planned Parenthood lawyers have argued in court, claiming if its federal funding is cut, women on Medicaid would lose "essential" care they can't receive somewhere else.