Remember that time the United States sued a package of diaphragms? No?

Well, it happened.

In 1932, Dr. Hannah Stone, a physician at one of Margaret Sanger's birth control clinics, ordered diaphragms from Japan to distribute to patients. The package was seized and confiscated by U.S. Customs under the Tariff Act of 1930, which was supported by the Comstock Act.

When Dr. Stone ordered the diaphragms, she and everyone involved, including Sanger herself and her attorney, Morris Ernst, expected them to be seized. They had been looking for a test case to challenge the Comstock Act on the basis that the law interfered with the shipment of medical supplies.

U.S. v. One Package, as it's commonly known, was tried in the United States Court of Appeals for the Second Circuit. The court ruled that Comstock Laws could not interfere with contraceptives ordered by a licensed medical doctor for medical treatment.

Writing for a unanimous court, Justice A.N. Hand wrote:

While it is true that the policy of Congress has been to forbid the use of contraceptives altogether if the only purpose of using them be to prevent conception in cases where it would not be injurious to the welfare of the patient or her offspring, it is going far beyond such a policy to hold that abortions, which destroy incipient life, may be allowed in proper cases, and yet that no measures may be taken to prevent conception even though a likely result should be to require the termination of pregnancy by means of an operation. It seems unreasonable to suppose that the national scheme of legislation involves such inconsistencies and requires the complete suppression of articles, the use of which in many cases is advocated by such a weight of authority in the medical world. (Source)

Practically, U.S. v. One Package meant that doctors were free to prescribe contraceptives to their patients. Sanger declared, "The birth control movement is free." (Source)