Some men do have a problem with women in the workplace based solely on gender. The challenge for women in business is what to do about this situation, and how to handle this powerful feeling of unjustified bias. I have experienced this myself. There is a great emotional and intellectual conflict associated with making the judgment that a man acts towards you based solely on gender. This overhead makes it harder to resolve.
Gender bias can be a reasonable conclusion.
There are serious remedies for this. But there also can be, and usually are, other issues influencing workplace behavior and how both men and women perceive it. A fair-minded woman will always take a personal inventory when this situation occurs. After all, the only person you can confidently control and influence is yourself. Step outside the situation as best you can and observe.