There has been big debates about this in Norway for as long as I can remember. One of the arguments for the "father's quota" is that when fathers were not "forced" to take at least some parental leave, there was an implied policy many places that as a father you left all the parental leave for the mother, with all the inequality that follows. Personally I am very pro the father's quota, as no employer can now (implicitly) force me to not take it.