A Male heir is also widely known in the west. Though it has since died down a bit.
In Western culture, it is the man who carries on the family name. And that is important to many people.
The IDEA is that men are important to society, and that men are more generally treated equally. Women, are more or less just there to serve men. And that can still be seen today, though less prominent today.
And this is a "why do you think" question. And that is what I think.