Question for our Danish friends

It is a good question, and I'm not really sure why.
My best bet would be, that it is because there isn't than many different last names. The five most common last names are held by around 20 % of the population, and by far the most of all last names use the 'sen' ending, meaning son of, which people find kinda boring for some reason, so parents are more disposed toward giving the children a middle name to make them more unique.

I have three names. My first name, my mother's last name and my father's last name. This is common. Others may inherit more than one name from one parent.

It is also true, as jepaan suggested, that since my father's last name is a '-sen' name, it might seem a little anonymous on its own.

Women who get married may take their husband's last name in addition to or instead of their own. Or not at all.

--
IMDb Poll http://www.imdb.com/poll/