The United States federal law criminalising any form of female genital cutting was passed by Congress as an addition to the U.S. Cade Title 18, Crimes and Criminal Procedures, and listed in Part I, Chapter 7, “Assault”. In other words, it categorises female genital cutting as an assault. The most relevant paragraph reads: "(a) Except as provided in subsection (b), whoever knowingly circumcises, excises, or infibulates the whole or any part of the labia majora or labia minora or clitoris of another person who has not attained the age of 18 years shall be fined under this title or imprisoned not more than 5 years, or both." Sub-section (b) allows the operation to be performed if it is “necessary to the health of the person on whom it is performed, and is performed by a person licensed in the place of its performance as a medical practitioner”.

Source: 18 U.S.C.A. § 116. Female genital mutilation

Congressional Findings

Justifying the passage of the law, Congress advanced the following arguments:

The Congress finds that:

  1. the practice of female genital mutilation is carried out by members of certain cultural and religious groups within the United States;
  2. the practice of female genital mutilation often results in the occurrence of physical and psychological health effects that harm the women involved;
  3. such mutilation infringes upon the guarantees of rights secured by Federal and State law, both statutory and constitutional;
  4. the unique circumstances surrounding the practice of female genital mutilation place it beyond the ability of any single State or local jurisdiction to control;
  5. the practice of female genital mutilation can be prohibited without abridging the exercise of any rights guaranteed under the first amendment to the Constitution or under any other law; and
  6. Congress has the affirmative power under section 8 of article I, the necessary and proper clause, section 5 of the fourteenth Amendment, as well as under the treaty clause, to the Constitution to enact such legislation.

Section 645(a) of Div. C of Pub.L. 104-208

Why these observations would not apply just as strongly to circumcision of a boy is not obvious.