No, you should never disclose someone's transgender status or gender assigned at birth without their explicit permission. Medical ethics and privacy principles establish that transgender identity and history are deeply personal information that only the individual has the right to share. This confidentiality requirement applies regardless of how you learned this information.
Guidelines from leading medical organisations emphasise that sharing someone's transgender status without consent can expose them to significant risks including discrimination, harassment, or violence. Research shows that transgender individuals face higher rates of workplace discrimination, social rejection, and physical harm when their status is disclosed without permission. These risks make confidentiality not just a matter of courtesy, but a fundamental safety issue.
The only exception would be if the person has given you clear, explicit consent to share this information with specific people for a particular reason. Even then, professional standards recommend limiting disclosure to what is absolutely necessary and relevant to the situation. Healthcare providers, employers, and family members all have responsibilities to protect this private information.
People often wonder about situations involving medical emergencies or legal requirements, but these scenarios typically involve the individual's own disclosure or specific professional protocols rather than informal sharing by others. Understanding these boundaries helps create safer, more respectful environments for transgender individuals in all aspects of life.