In Spain of course your parents have 2 surnames too.
So your first surname is your father's first surname, his 2nd surname is dropped ( first surname of his mother )
Your second surname is the first surname of your mother, her 2nd gets dropped too.
In the end always the name line of the females get dropped.
That's so shitty. In the Netherlands they've just started to allow 2 surnames. One of the best proposals I've heard is that you would take your father's father's name, and your mother's mother's name. That way men continue the male name line, and women continue the female name line.
Historically, yes; however, they passed a law some years ago to allow for the mother's surname to be the first surname, as it happens in Portugal. Nonetheless I am not sure how popular this is.