At least 10 states have introduced or passed legislation to narrowly define what it means to be “male” or “female.” Such laws have myriad impacts for transgender people — from making it impossible to update birth certificates, driver’s licenses and state IDs with one’s correct gender marker, to barring people from using bathrooms that align with their gender identity.

“What they’re trying to do is excise transgender people from the protections of state code,” said Sharon Brett, an attorney at the ACLU of Kansas, referring to lawmakers in her state who passed a law last year that narrowly defines sex.

Such laws make it harder for transgender people to go anywhere where ID is required — airport security, banks, job applications, voting booths — and could make them even more vulnerable if dealing with police.

“If you are forced to carry ID documents that do not reflect how you live in the world, but rather reflect only the genitals you had when you were born, that essentially outs you as transgender to anyone you present your identification to in the normal course of business,” Brett said.

Republican lawmakers claim these laws provide necessary clarifications on the distinctions between sex and gender and will protect women and girls in locker rooms and bathrooms — even though there is no evidence suggesting that transgender people pose a risk to public safety. Trans and nonbinary teens are actually at greater risk of sexual assault when schools deny them access to locker rooms and bathrooms that match their gender identity, according to a 2019 study in the journal Pediatrics.

In early January, Missouri state Rep. Adam Schnelting (R) defended bills HB 2308 and HB 2309, which define sex as “the presence or absence of a reproductive system that produces, transports, and uses eggs or sperm for fertilization, regardless of any developmental or genetic anomaly or historical accident.” He insisted he wasn’t debating “whether the medical community is right or wrong,” and said he wanted to protect kids from people who take advantage of trans-inclusive policies. But when pressed by Democratic state Rep. Ashley Aune for any example of this nefarious behavior, Schnelting couldn’t name one.

“Predatory and violent behaviors targeting women and children, whom these bills are claiming to protect, are already criminalized and enforceable, without targeting a population that is itself most at risk of experiencing violence and harm,” said Zachary DuBois, an assistant professor of biological anthropology at the University of Oregon. DuBois helped co-author a statement from seven American biological associations condemning “legislation that is rooted in and maintains a rigid binary conceptions of sex and gender.”