I saw an email between a trans man who had sex with men before transitioning and red cross who said they couldn't donate blood because they're male.

Edit: here's an article based on a different experience, cw for transphobia

https://www.msn.com/en-us/news/us/a-transgender-man-was-not-allowed-to-donate-blood-unless-he-identified-as-female-on-his-paperwork/ar-BB19RUzo