Iowa Governor Kim Reynolds, a Republican, on Thursday signed a bill into law that bans transgender women and girls from playing on sports teams that match their gender identity.
At her signing ceremony held at the Iowa Capital rotunda, Reynolds claimed that the law would advance women's equality.
"Forcing females to compete against males is the opposite of inclusivity and it's absolutely unfair,"
she told the assembled crowd.
The law covers public schools and universities.
Iowa joins 10 other states with similar bans.
The law also allows students who believe they have been harmed by a violation of the law to sue their school districts or athletic associations. That is, private educational institutions that allow transgender athletes to participate could face lawsuits.
Sam Ames, director for advocacy and government affairs at The Trevor Project, which provides crisis intervention and suicide prevention services to LGBTQ youth, said that the law would hurt transgender students.
"Sidelining trans students will only contribute to social isolation and stigma that fuels bullying and mental health challenges for young trans people – issues they already face at alarming rates," Ames said.
A small group of protesters with LGBTQ group Iowa Safe Schools attended Thursday's ceremony. They silently held signs that said "protect my innocence" and a transgender flag.