That's what my daughter's doctor told me when she was around 6 months old. I think she was encouraging me to put her down a little more often, but her words had the opposite affect on me.
I'm a baby holder. I LOVE to hold my babies. And rock them, and sniff them, and sing them little songs.
And if holding them keeps them from finding the motivation to crawl, or roll, or walk, or get older, or become independent, well, then, you had better believe that I'm going to keep on holding on.
It didn't work with the other two. Neither had any problems mobilizing. Am I deterred? Ha! I don't give up quite that easily.
In fact, I might just keep this one in a papoose until Kindergarten. Do you think he would be teased if I dropped him off in a back carrier?