I freaked out the first time my DD slept on her tummy (would have been about 7mths)she had a shocking head cold and I guess it probably helped her to breathe clearer or was more comfortable I called the child hotline who told me that although it wasn't ideal she was obviously more comfortable this way. It wasn't till after this that I was looking at a photo album of myself at the same age and found a photo that could easily have been my daughter, the sleep position was identical. I guessed there was no point in fighting it past this point. She's now 17mths and a fully fledged tummy sleeper!!!