Final answer:
Generally, it is false that employers can legally require employees to use restrooms based on their birth sex, due to federal protections against gender identity discrimination and OSHA recommendations.
Step-by-step explanation:
The legality of employers requiring employees to use restrooms that align with their birth sex is a complex issue on federal, state, and local laws, as well as court rulings. According to a 2020 Supreme Court ruling, federal legislation now protects employees from discrimination related to sexual orientation and gender identity, which includes protections for transgender individuals in the private sector. Moreover, the Department of Labor's Occupational Safety and Health Administration (OSHA) has recommended best practices suggesting that all employees should have access to bathroom facilities that correspond to their gender identity. As such, the statement that employers can legally require employees to use restrooms based on their birth sex is generally false, especially considering federal protections against gender identity discrimination and best practices recommendations from OSHA.