Intrigued by the suggestion to fly an all-female shuttle crew, NASA has tapped former astronaut Rhea Seddon to lead a committee to assess if gender, age and other attributes should be taken into consideration when making flight assignments and developing measures to counteract the harmful effects of weightlessness.

The findings could prompt NASA to assign an all-female payload crew to serve as medical research subjects aboard a future shuttle mission.

As NASA shifts from two- to three-week shuttle flights into months-long missions on the International Space Station, questions are being raised about the types of people who fare well in orbit, as well treatments to counteract bone and muscle loss, cardiovascular deconditioning and other degerative conditions associated with zero-gravity.

"The reason why you would fly an all-female payload crew is because the place where you can take the most data is a dedicated mission," said Arnauld Nicogossian, NASA's head of life and microgravity sciences office, who came up with the idea of an all-female payload crew.

Although NASA has been flying women since 1983, the agency has not made a concerted effort to isolate gender as factor in scientific studies.

"No one has ever looked at hormone levels in women in space," said former astronaut and physician Seddon, who met with her committee this week in Houston.

"If NASA really does want to do the science of female physiology on a reputable science mission, for all the right reasons and with all the right equipment, then I think that would be fine," Seddon said. "I don't think they should pull together a female crew for PR reasons."

Added Nicogossian, "We have a lot of data on white males. Now people are starting to be very sensitive to the needs of other groups. Not everything you can extrapolate from one group or another."

Seddon's committee is expected to complete a report and make its recommendations to NASA early next year.