Not meeting the milestones "on time" is always nerve-wracking. That being said, I've known of several boys who were like that -- taking their time talking, but they were just fine. (Hey, that even reminds me of "A Wrinkle in Time" when the 3 yo went from not talking at all to sounding like an adult literally overnight. Ok, I know that's fiction.)
The delayed talking could be due to a dozen different reasons -- some benign, some not so. Do you have some other indication that something might be wrong with his hearing? Or his ability to hear pitch? I imagine, for instance, that he understands way more than he speaks. Is the mommy/daddy thing one more piece of evidence to add to an ever-growing pile, or is it an isolated insident that stood out because you're trying to figure out what's going on with your ds?
