According to a recent article in Parents Magazine, a new study, published in May in the journal Early Human Development, suggests that tummy time may be irrelevant. This practice was recommended for babies to enhance their motor development, as infants are now being put 'back to sleep' to prevent SIDS.
Studies are now finding that the "Back to Sleep" Campaign is a necessary safety practice and is NOT adversely affecting motor development.
The take-away for parents is that some supervised time on their tummies is fine, although not required.
Of course check with your pediatricians for their individual thoughts and ENJOY your babies!