By Irene Klotz

HOUSTON (Reuters) - Teen-age boys, are you tired of embarrassing questions about when you last changed underwear? Japan's space scientists may have just the answer -- a line of odour-free underwear and casual clothing.

Koichi Wakata, the first Japanese astronaut to live on the International Space Station, is testing the clothes, called J-ware and created by textile experts at Japan Women's University in Tokyo.

"He can wear his trunks (underwear) more than a week," said Koji Yanagawa, an official with the Japanese Aerospace Exploration Agency.

Wakata's clothes, developed by researcher Yoshiko Taya, are designed to kill bacteria, absorb water, insulate the body and dry quickly. They also are flame-resistant and anti-static, not to mention comfortable and stylish.

Japanese astronaut Takao Doi gave the clothes a trial run during a shuttle mission last year. Even after a vigorous workout, Doi's clothes stayed dry.

"The other astronauts become very sweaty, but he doesn't have any sweat. He didn't need to hang his clothes to dry," Yanagawa said.

J-ware should reduce the amount of clothing that needs to be sent to the space station, which has no laundry facilities. Toting cargo into orbit is expensive, so having clothes that stay fresh for weeks at a time should result in significant savings.

The Japanese space agency plans to make the clothes available to NASA and its other space station partners once development is complete. A commercial line also is in the offing.

Taya also is working with clothing manufacturers Toray Industries and Goldwin. on clothes that have a microscopically thin chemical layer in the materials.

Wakata, who arrived at the station last week for a three-month stay, said on Sunday that the clothes appear to be working.

"Nobody has complained, so I think it's so far, so good," Wakata said.

(Editing by Jane Sutton and Cynthia Osterman)