Now that's a bit of a sexist statement!
What are the duties required as a woman exactly? Cooking dinner? Raising the kids? Cleaning the house? If you believe these tasks are still the sole duty of women, then you're just as much a victim of accepting sexist societal norms as the men who deny their emotions, of whom you criticize!
And I mostly agree with red_ed: society has always said men have to be stoic. Just think about what the adjective "masculine" implies: strong, brave, proud, dominant/aggressive, sexual, a leader, etc. Nowhere will you see it including sensitive, emotional, and open -- those are classic characteristics of femininity, for better or worse, and women too are trained to evaluate men by the classic masculine traits, which only makes it even less likely men will change.