WASHINGTON, D.C. ? Keepsake sonograms have become a popular item with many young parents – from Tom Cruise to the couple next door. It’s a practice many physicians would like to discourage.

The latest concern comes from a study that suggests, in mice at least, that ultrasound can affect the development of the fetal brain.

Even so, researchers say the findings should not keep pregnant women from having ultrasound scans when needed for medical reasons.

When pregnant mice were exposed to ultrasound, a small number of nerve cells in the developing brains of their fetuses failed to extend correctly in the cerebral cortex.

Dr. Joshua Copel, president-elect of the American Institute of Ultrasound Medicine, said his organization tries to discourage “entertainment” ultrasound, but considers sonograms important when there is a medical benefit.