(NBC) -- Beginning Wednesday every employer in the United States is required to provide free contraception to female employees.
That's the most controversial of eight new rules under President Obama's health care reform law.
Health plans now must provide free screening for everything from STDs to diabetes.
While democrats are celebrating, senate republicans tried again to repeal the law known as "Obamacare".
Religious and conservative groups are most upset about the contraceptive requirement for employers.
"It forces an impossible choice on them, either they've got to violate their conscience or they'll be faced with extraordinary fines," says the Heritage Foundation's Jennifer Marshall.
The rule is already being challenged in the courts by foes of the president's health care law, who are hoping to back to the Supreme Court and fight again.
A Colorado company won a reprieve from a federal judge last week, opening the door for more challenges.