One of the main arguments behind so-called “bathroom bills” — which restrict a transgender person’s public bathroom usage to the gender on their birth certificate rather than whatever aligns with their identity — just took a major beating.

Researchers at the UCLA School of Law’s Williams Institute, a think tank focused on gender identity, released a study Wednesday showing there's no statistically significant evidence behind the charge that transgender bathroom access and bathroom-related crimes are related.

Because Massachusetts passed an anti-discrimination law that some say threatens public safety — and are now trying to overturn in a ballot initiative — the researchers zeroed in on restroom crime reports in the state before the anti-discrimination provision was adopted.

The researchers found no increase in crime and no difference between cities with and without the restrictive bathroom policies in the first-of-its-kind study. That’s a blow to activists who argue trans rights risk safety to women and children in the restroom,.