According to Daily Caller:
By fall 2017 Washington state public schools will begin teaching gender expression to kindergarteners under newly-approved health education learning standards that designate sexual health a “core idea” of public K-12 education.
While some aspects of sexual health aren’t taught K-12 (HIV prevention begins in fourth grade), one component of sexual health titled “Self-Identity” begins in kindergarten, where students will be expected to “Understand there are many ways to express gender.”