Complex sentence: In South Korea, it is possible for a transgender individual to change their legal gender, but it depends on the decision of the judge for each case, although since the 1990s, sex change has been approved in most of the cases.
Split into simpler sentences: In South Korea, it is possible for transgender individuals to change their legal genders, although it depends on the decision of the judge for each case. Since the 1990s, however, legal sex change has been approved in most of the cases.