"Female Astronauts Said To Face Discrimination Over NASA's Space Radiation Concerns"

Article here. Excerpt:

'Female astronauts have fewer opportunities to fly in space than men partially because of strict lifetime radiation exposure restrictions, astronauts say.

Both male and female astronauts are not allowed to accumulate a radiation dose that would increase their lifetime risk of developing fatal cancer by more than 3 percent. A six-month mission on the International Space Station exposes astronauts to about 40 times the average yearly dose of background radiation that a person would receive living on Earth, NASA spokesman William Jeffs said in an email.

While the level of risk allowed for both men and women in space is the same, women have a lower threshold for space radiation exposure than men, according to physiological models used by NASA.
...
NASA follows radiation exposure recommendations established by the National Council of Radiation Protection and Measurements. The exposure limits for women are about 20 percent lower compared to men "largely due to additional cancer risk for woman from breast, ovarian, and uterine cancers," Jeffs told SPACE.com.'