My wife constantly corrects me when I say things like "there is no reason..." or "there's no point..." etc. She tells me to say "there is not a reason..." or "there is not a point."
However, when I do a Google search for 'english gramar "there is no reason"', I get a number of links to English-related websites like this one where the "experts" are using these terms.
Getting to the point: Is it ok to say "there is no reason..."?
P.S. (Yes, I know my question mark is on the wrong side of the quote, but I am a computer scientist and it makes more sense to me that way).
Well, tech. . .nically, she's right but you're right about the placement of the question mark. The question mark is not part of 'there is no reason', so it should be outside the quotation marks.
About 'no' and 'not'. Here's the whathaveyouz. "I have" means, I possess, whereas "I have no shoes" means, I possess nothing, which sounds pretty much OK first glance, but at the root of the semantics, what's actually being expressed is a contradiction: I have something but that something doesn't exist. How can you have something that doesn't exist? I believe that's the meaning your wife is drawing on when she says, "Say, There is not a reason."
The same holds true for the verb "is", which expresses existence. "There is no reason" expresses a contradiction: There exists a thing, and it's a non-thing. Now how can a non-thing exist?
To avoid the contradiction, speakers add 'not' to the verb, like this,
There isn't a reason.
By adding 'not' to the verb, we negate the verb, so a positive expression "is" (exists) becomes a negative expression "isn't" (does not exist). 'a reason' is a thing that doesn't exist.
Now that's not to say that "There is no reason" is not acceptable, i.e., not used by native speakers, because you're a native speaker, as am I, and we both, among many others, including G.W. Bush, say it. So is it unacceptable? Well, that all depends on whether or not you want to argue the semantics of it all.
In short, tech. . .nically, "isn't a reason" is semantically clear, whereas 'no reason' is semantically awkward. But 'no reason' is shorter, and speakers seem to know what it means, so it's effective in terms of communicating your wants and needs. If you like it, use it, and if you come across someone who doesn't like it, then you could always respond with, "Semantics!"