Before reading through here and seeing there are a couple of people who have either had late crawlers or crawled late themselves, I was going to say yes I'd be concerned about the not crawling but not about the walking. Even so, for me I'd still probably be getting concerned about the not crawling and in particular if he's not really doing anything other than sitting.

So, my questions are the same as the others... what other milestones has he met, does he have older siblings etc. The whole picture. Does he move around at all in any way? Like Janie said, she bum shuffled... so did Oskar, he didn't crawl until after he walked.