It is perfectly safe as long as you are there to help and support him. My child had physical therapy at 10 days of age for 2 years at a highly successful and well qualified private center. I can't tell you all the positions they were putting him in so that he would be able to start bearing weight and be able to get into the correct patterns for movement. He did great. But the key is not forcing the baby into any position that is not natural, and being there to hold and support. That said, babies do crawl when they are ready, but there is no harm in helping to build some of the strength and muscles that it takes for that to begin based on my experiences with the professionals. Since my first one, I have done this with all my babies. Tummy time is the most important thing you can do, and getting him up on his hands and knees definitely will not hurt. Also, crawling to the professionals is critical for development, don't skip it!
at 11:17 PM on Jan. 13, 2013