I will never forget- I was working a blood drive down in Mennonite country in Illinois and a young man came to our bus to donate. You screen people by asking if you’re a man who has had sex with a man (that rule is being challenged as they are rethinking the risks of gay men and blood donation). He denied this question but asked if it was ok if you had sex with a horse.
We literally had to contact the medical director to find out- he was allowed to donate.