You must be 18 years or older. You must weigh more than 110 pounds. You must be in good health. Simple rules for donating blood, right? Not necessarily. You must not be a male who has had sexual contact with another male in the last three months. You may be able to donate blood as a trans man … but not if you’ve had sex with another man in the last three months. If you are an individual who identifies as female and has had sex with a man, you may be eligible to donate blood.