I agree that the identification of dominance as a male property and passiveness as a female property is problematic. However I think this association is not a complete social construct. Biological factors are certainly involved. Hormones like testosterone does contribute to assertive, dominant attitude, whereas oxytocin contributes to gentleness. In the context of our ancestral environment, such distribution of hormones and the labor divisions it entails makes sense, and might have been advantageous for our survival. However, the situation has changed, especially since the industrial revolution. Less and less brute strength is required to survive and succeed. However, the difference in biological constitutions still creates a difference in term of drive and assertiveness between the two sexes, in my opinion, and this has a bearing on success, social roles and behaviors. Social prejudices doubtlessly contribute to this as well.
I will try to outline a few problems that I see:
Absolutizing and exaggerating biological differences: Just because men in general has more testosterone doesn't mean this particular man is more assertive than this particular women. To be concerned with abstract generalization more than the specific circumstance is bound to lead to error in judgment.
Confusion between is and ought: Just because a man has more testosterone doesn't mean he should strive to be dominant and aggressive.
Gender essentialism: just because a specific paradigm of gender roles has been successful and advantageous in the past doesn't mean it should be preserved in modern society. Things change.
Last but not least, gender favoritism: objectification is in any case dehumanizing whether done by one sex or the one. And even if it is inevitable, it should be minimized. It is best to co-operate and strive to bring out the best potentials of both sexes.
–--------
Bonus:
I have always wanted an excuse to post this excellent explication of Ontological Objectification (or Nihilism) as understood by Heidegger, so here it is, although it is not exactly about gender:
[hide] http://i.imgur.com/zC66sNA.png
http://i.imgur.com/yeRkxGK.png
http://i.imgur.com/eTwuQkJ.png [/hide]It is precisely because we are oblivious to such subtle changes in our perception that we are easily swept along by the flow of modern nihilism. Minor 'objectification' of everyday entities (i.e. they are tripped of their primordial meaning disclosed in life-world context and come to be seen as mere present-at-hand objects, as means to an end) sets the premise for the objectification of human beings.
That is not to say nihilism is necessarily wrong though.
And the subject-object paradigm is useful for many tasks.
How would you describe the status of gender roles as relates to society though? After all, to some extent all such gender roles are different depending on culture.
Such as your culture, the Vietnamese culture.