So here's what I do to help remedy that. Act it out. That's right. I would act out the scenes of the character's lines and reactions. This goes for the females too. When I'm alone I feel no shame doing every single little detail. I do all of it! And doing this method has helped me develop my team to greater lengths than they were originally made for. But there are characters that I did feel strange about being able to portray. Strange as in questioning if that kind of persona exists in me. But that's going off topic.
Point is, once I decided to stop doubting my ability to understand them and realized in some sense that each of these personas are in me, I no longer feared who was put on paper. Because let's be honest. No one can understand your characters better than you. They're your children. Don't shun their actions, embrace them!