The U.S. Conference of Catholic Bishops are threatening to sue the Obama administration over its mandate that health insurance cover birth control for women.

In a letter to federal regulators, the bishops said if Congress fails to act quickly, the court is its only recourse.

Several small Catholic universities have already filed suit over the policy because of religious and moral objections.

Meanwhile, the Roman Catholic Archdiocese of Washington objects to Health and Human Services Secretary Kathleen Sebelius being invited to speak at Georgetown University, Friday.

In a statement, the archdiocese calls Sebelius the "architect" of the birth control mandate.

"The Secretary's presence on our campus should not be viewed as an endorsement of her views," Georgetown University President John DeGioia said.

But the archdiocese said the invitation shows a "disregard" for Catholic bishops and others defending freedom of religion.