In many countries it is expected that a man should ask a woman on a date. But in some other countries (Scandinavia, or the Wodaabe tribe in Africa) it seems to be the other way round (or at least the other way round is acceptable.)
I have noticed that when alcohol is involved women are more likely to approach men (apparently alcohol increases the level of testosterone in women).
Thus psychologically speaking, is this a cultural norm or something innate.
Also, mathematically speaking, it seems that it is better that only one gender does the asking. At least most mathematical models assume this. But is this decided biologically or culturally?
(And are there animals that differ in this regard?)