JUNEAU — The emergence of impotence drugs like Viagra may end up reducing demand for body parts from threatened or endangered species that are used for traditional Asian cures, a new study says.

The study concludes that people who use traditional Chinese medicine are switching to Viagra, Cialis and other Western drugs to treat their impotence.

The two main authors, Alaskan brothers Bill and Frank von Hippel, published their conclusions in the journal Environmental Conservation this month based on their studies of Hong Kong men over 50.

The authors surveyed 256 men seeking treatment at a traditional Chinese medicine clinic.

They found that while the men continued to use traditional Eastern cures for ailments such as gout, arthritis and indigestion, they were more likely to be using Western medicine for impotence. Several had switched from traditional methods to the Western drugs.

"As a result, they are using fewer animal parts from threatened species," said Frank von Hippel, a University of Alaska Anchorage biology professor.

Von Hippel said the findings support their research that Western impotence drugs may be an unintended wildlife conservation aid. Seals, sea lions and walruses are the animals most likely to benefit because they are often poached for their genitalia, he said.

"We think that market has pretty much collapsed from the advent of Viagra and other Western treatments," von Hippel said.

Other animals used for impotence cures include sea horses, geckos and deer, whose velvety antlers are used in traditional medicine. Tigers, rhinos and bears also are believed to cure impotence, but because they are used in many aspects of traditional Asian medicine, the authors do not believe the Viagra boom will have much effect on them.

Frank and Bill von Hippel, who is a psychologist at Australia's University of New South Wales, have been researching the topic since 1998. Their past work has generated skepticism, and this study of trends among users of traditional medicine was conducted to answer some of those skeptics, Frank von Hippel said.

Their latest paper was funded by Pfizer Inc., the maker of Viagra. Frank von Hippel said some of the $46,342 grant is left to continue their research. Von Hippel said the brothers are considering a similar study of men in India.

Conservationists' initial reaction to the study was uncertainty. The Alaska Wildlife Alliance declined to comment at all. Buck Lindekugel of the Southeast Alaska Conservation Council took a stab.

"It doesn't sound implausible," he said. "Whatever we need to do to keep these animal populations healthy and productive, it makes sense."