Quoting Jessica & Kaleb:" LO sat up around 8mos and crawled at like 9/10 ur LO seems to be doing fine, and at 5mos old its hard ... [snip!] ... Kaleb was fairly behind with physical things until he was 10mos olf, he crawled, learned to stand and walked all in a month"That's not behind at all!
Quoting Venus Penis Trap.™:" <blockquote><b>Quoting Angie Mother of Boys:</b>" Sit up supported 4-5 months. Unsupported ... [snip!] ... 6 or so. Well unsupported 8-9 months. He sounds okay. Rolling is good. Does he scoot on his belly?"</blockquote> No."He's really 4 months. So even though he isn't scooting, I wouldn't say he is behind.