A sonogram society has a message for Tom Cruise: leave the sonograms to the experts.

Cruise told Barbara Walters last week that he'd bought his own sonogram so he and Katie Holmes could watch their baby growing inside her belly.

The Society of Diagnostic Medical Sonography says it's worried that Cruise will do something wrong to hurt the fetus.

The society says it takes a lot of training for an sonographer to get certified. It says "reading the manufacturer's manual or having a one-hour orientation is not sufficient."