Ok, aside from y'all's inability to spell the word "retarded", let me break it down for you. In the Torah, There is a commandment that states, "you shall not boil a kid (the young of a goat) in its mother's milk."
Now, here is where a principle can be demonstrated. The Torah gives certain commandments. But the Rabbis who EXPLAINED the Torah wanted to "build a fence around the Torah". The idea was that if you didn't break the laws surrounding the laws, you would never get close enough to breaking the laws themselves. Now that probably doesn't make much sense. Let me explain.
So, you have the Torah, with its rules that allow or forbid certain things. You don't want to break those rules. Then, around that, you have a set of rules that exist such that, if you follow that larger set of rules, you won't come anywhere close to breaking Torah rules.
The rule you asked about is one of those. Its not in the Torah. Its one of those that the Rabbis legislated as a rule that builds a fence around the Torah. If you can't even mix milk and meat on your plate, you certainly aren't going to be able to boil a kid in the milk of its mother!
Now, before you ask the question, DO I mix milk and meat? Yes, I do. I follow strictly biblical commandments, unless I see extraordinarily good reasons to follow Rabbinically ordained ones. Obviously, if I am at Shul, or an Orthodox Jew's home, then I will follow the more strict practices. But in my personal life, I tend to disregard Rabbinical laws unless I see the value in them peronally, and there are many that I do. But there are many that I don't, and this is one of them.