I know that parents in Russia believed it was better for infants to sleep on their stomachs. But who knows, it could have been because they didn't want their children to have flat heads I know I've slept on my stomach my whole life. I definitely see the stomach sleeping and crawling connection. My mother says that when she saw me get tired she would lay a mat or blanket in my path and I would crawl onto it and go to sleep right there. [Then once I was out, she would then move me somewhere else, apparently I didn't like getting put to bed while awake]

I'm really happy to hear that stomach sleeping for infants isn't dangerous and I would want to see a reference that your professor used because with the US medical authorities "put baby to sleep on their backs" is the official recommendation.

This is the American Academy of Pediatrics and they say to always put babies to sleep on their backs:

http://www.healthychildren.org/English/ages-stages/baby/sleep/pages/A-Parents-Guide-to-Safe-Sleep.aspx?nfstatus=401&nftoken=00000000-0000-0000-0000-000000000000&nfstatusdescription=ERROR%3a+No+local+token

To prevent SIDS: "Always place babies on their backs to sleep"

http://www.nichd.nih.gov/health/topics/sudden_infant_death_syndrome.cfm