It's the story of two FBI agents. They investigate odd stories ( about aliens and other scary monsters). Fox Mulder is the believer and Dana Scully the skeptic. But what I really like about the X Files is that almost every subject could be real. They speak about nowadays issues which is very interesting : clonage, the problem of abondonning our grandpas and grandmas in old people's homes when they become too old for us to look after them (see episode Exelsus Dei (season 3)
The X Files actually don't speak about monsters but about men, what can men become because men can do more horrible things than what we see on The X Files.
It reflects our fears (the fears we can feel in our society) but also our dreams : we all want to believe that there is something other than this life, we all would like to stay young forever and we always will, that's why X Files is up to date and will always be.
X Files is created by Chris Carter. It's a really good series because I think it's the first series where a man and a woman are considered as equals. I know that Fox Mulder is almost always right but Dana Scully is really intelligent too and Mulder needs her help to resolve the different cases.
Scully is a good example for every girl and woman : she's independant, intelligent. She does a good job.
Many girls want to look like her in the real life and I'm pleased for that.
After her, many TV series will use a female as heroine or will consider women are men's equals : Alias, Lost,Bones, Cold Case , ...