&gt; &quot;You know, we can&#x27;t say for certain; perhaps at that time dropping the landline was in effect risky behavior.&quot;<p>No, that&#x27;s their explanation for <i>why</i> there might be a correlation. It&#x27;s quite clearly not something they&#x27;re actually certain about.<p>The only fact the CDC believes is that cell phone exclusivity correlates with risky behaviors.