A health care provider may not provide gender transition procedures to any individual who is under 18 years of age. A health care provider may not refer any individual who is under 18 years of age to any health care provider for gender transition procedures.

A health care provider licensed under this title may not knowingly engage in or cause any of the following practices to be performed on a minor if the practice is performed for the purpose of attempting to alter the appearance of, or affirm the minor's perception of, the minor's gender or sex, if that appearance or perception is inconsistent with the minor's sex: (a) Prescribing or administering gonadotropin-releasing hormone analogues or other synthetic drugs used to stop luteinizing hormone and follicle-stimulating hormone secretion, synthetic antiandrogen drugs used to block the androgen receptor, or any drug to suppress or delay normal puberty; (b) Prescribing or administering testosterone, estrogen, or progesterone to a minor in an amount greater than would normally be produced endogenously in a healthy individual of that individual's age and sex;

In order to protect the rights of children, families, and teachers, and maintain order in K-12 public schools, the legislature enacts the following provisions [...] (a) An employee or contractor may not use a name to address a student other than the name listed on a student's birth certificate, or derivatives thereof, without the written permission of a student's parents or guardians. (b) An employee or contractor may not use a pronoun in addressing a student that is different from that student's biological sex without the written permission of a student's parents or guardians.

Interschool athletic activities and other interschool extracurricular activities of an athletic nature, including those administered by a school district board of directors under RCW 28A.600.200, must be organized using the following groupings for the purposes of participation and competition: (a) Students who have the same kind of sex chromosome (xx) who identify as a woman or girl; (b) Students who have the same kind of sex chromosome (xx) who identify as a man or boy;16 (c) Students who have two different kinds of sex chromosomes (xy) identify as a man or boy; (d) Students who have two different kinds of sex chromosomes (xy) who identify as a woman or girl; and (e) Students who do not meet the criteria in (a) through (d) of this subsection. (2) For the purposes of this section, a student's eligibility for a particular grouping may be determined by any medical documentation that demonstrates the chromosomal makeup of the student.