The Administrator of the Transportation Security Administration may not use the "X" gender designation in the TSA PreCheck advanced security program. The Administrator may permit applicants to and participants in such program to select from only "Male" or "Female".

DEFINITION.—The terms "male" and "female" mean the biological classification of male and female sex in the context of reproductive potential or capacity, as in7 dicated by sex chromosomes, naturally occurring sex hor8 mones, gonads, and nonambiguous internal and external genitalia present at birth.