As Paula and Martin Theriault stare wide-eyed at the flat-screen TV, a clearly detailed, full-motion image of their unborn daughter leaves them breathless.

"Wow, it was pretty exciting, just seeing the face," Paula Theriault says as an ultrasound technician with Baby Images Inc. moves a small scanning device across her round belly.

"You can really see the details of the eyes, the face, the nose ... you can see her move."

The couple from Dieppe, N.B., has come to the new private clinic in Moncton to determine the sex of their child and purchase pictures and high-resolution video recordings -- services most hospitals won't provide.

Private, for-profit ultrasound clinics are popping up across Canada -- another chain, UC Baby of Mississauga, Ont., has expanded to 16 locations in five years -- even though Health Canada has issued a warning about the potential health risks associated with exposure to ultrasound for non-diagnostic purposes.

The federal department has established guidelines that state ultrasound images should not be used for non-medical reasons or for commercial purposes.

Ultrasound is a non-invasive technique that uses high-frequency sound waves to create images on a monitor of internal soft tissues and body cavities, such as a fetus growing in the womb.

"There really has been no proven harm, but when you put energy into tissue, there is a certain amount of heat that is generated, and whether that has any potential ill effect -- who knows?" says Dr. Andrew Ross, past president of the Nova Scotia Association of Radiologists.

But the federal warning means little because the regulation of ultrasound clinics is a provincial jurisdiction.

"It's an uncontrolled environment ... timing, power, all those sorts of things," says Ross.

"That's why all the professional associations are all very adamantly opposed to (using) a medical device for non-medical purpose."

The fact that many hospitals won't reveal the sex of a fetus is probably driving business to private clinics, Ross says.

Paula Theriault, who is expecting in November, says she just had to know whether she was having a boy or a girl "... to be ready, the room, and just to be set."

Linda Richard, owner and operator of Baby Images, says parents also want to be reassured that everything is fine with the fetus during the 30-minute session.

"People like to see five fingers and toes or check for cleft palates ... make sure everything is there," she says.

Richard, who is also a registered nurse at a Moncton hospital, says despite the warnings, she believes the technology is safe.

Tina Ureten started UC Baby in Mississauga in 2003.

The chain now has locations in six provinces.

Trained as a radiologist in Turkey, Ureten says private ultrasound services are operating around the world.

She thinks the concerns in Canada are more about politics than safety.

"There's no involvement of the medical professionals, and patients can decide for themselves," she says.

The cost of the service isn't cheap, ranging from about $100 for basic photos to $300 for deluxe video packages.

The fact that many people are unaware of the Health Canada warning is a concern for Jan Gilby, president of the Nova Scotia Society of Diagnostic Medical Sonographers.

"People are not making an informed and educated decision to go to these clinics," Gilby says.