I used to know a child who didn't get all her milk teeth - can't remember the exact details now (was over 15 years ago) but I have a feeling she only ever got the front ones & was subsequently fitted with some false back ones to eat with
your DS is late - ask if you can have a full mouth X-ray. I know it's not generally advisable for children, but that will show both milk & adult teeth forming in the gums. or else hang on for 6 months to see if nextphase's DC is the same as yours...
At 3.5 the last 2 molars are just coming through here. We had 16 teeth at 3yrs old. The dentist didn't bat an eyelid when we were there. But it did feel like we were the only ones still teething! Can you take him along to your next dentist appointment, and get them checked, just for peace of mind?
When should I start for worry that there might be a problem? DS is very nearly three and still doesn't have all his teeth. We're waiting for the top back ones to make an appearance, but there is no sign of them. I thought that they should have all of their teeth by now, certainly all his friends his age have had all their teeth for ages. Should I be worried?