I have personally used
Aldara (though I am a woman) and it caused
no abnormal bleeding in me. The worst I experienced was some blistering, red skin, itching, ulcerations, etc. While I'd have to reference it again, I saw nothing mentioned in the pamphlet included with the medication regarding blood in semen as a side effect. This doesn't sound normal, I'd see a doctor promptly just to be safe as this could be something quite serious.