Possible Duplicate:
Sentence Construction: “Just Because … Does Not Mean”
“just because… doesn't mean…”
I'm wondering if "Just because X doesn't mean Y" is a grammatical construction. I tend to say, "Just because X, it/that doesn't mean Y", because I don't think "because X" is a nominal phrase. If this is correct, then "The reason why X is because Y" must also be correct.
I'd call it grammatically correct. "Just because X" is the subject of the sentence. If you want to make it slightly less informal, I'd probably replace "Just because" with "The fact that" or something similar.
^_^ And, of course, this is assuming that your X is not something ridiculous like "pancakes".
"Just because pancakes doesn't mean syrup" would not be valid. On the other hand, "Just because they served us pancakes doesn't mean we're getting syrup" would be.
It doesn't follow strict grammatical rules, but it is so commonly used that you can safely use it in many circumstances. I would personally hesitate to use it in written communication unless I was striking a conversational tone.
The argument for it not being grammatical, is that "because" and "means" have the same (approximate) meaning, although they are different parts of speech, so you don't typically use them both in the same sentence.
Berlin's cold winters mean that the residents are well prepared for snow.
Berlin's residents are well prepared for snow because of the cold winters.
More formal constructs for the negative include:
It's not the case that because X, Y.
X does not mean that Y
