HR4138 would prohibit any office or agency under the executive branch from collecting data on a person's gender identity and would restrict the options under sex to "male" and "female."

The bill defines "female" as "an individual who naturally has, had, will have, or would have, but for a developmental or genetic anomaly or historical accident, the reproductive system that at some point produces, transports, and utilizes eggs for fertilization."

The bill defines "male" as "an individual who naturally has, had, will have, or would have, but for a developmental or genetic anomaly or historical accident, the reproductive system that at some point produces, transports, and utilizes sperm for fertilization."

The bill defines "gender" as "males, females, or the natural differences between males and females, unless such term is otherwise specified or used alone (rather than with or as an adjective modifying other words); and a synonym for sex; and does not mean gender identity, experienced gender, gender expression, or gender roles."

The bill defines "sex" as "the biological determination as to whether an individual is male or female." The bill also states that "gender identity" is not sex or gender.