Women deal with a lot of sexism and obstacles here on earth, so it makes sense that this sexism would follow them in to space. The first woman went into space in 1963, but it took another two decades for female astronauts to become common. Turns out there's a glass ceiling even outside of the earth's orbit.
Recently, author Mary Robinette Kowal published an essay called “To Make It to the Moon, Women Have to Escape Earth’s Gender Bias" exploring the ways in which sexism here on earth prevented women from making strides in space. In response to her essay, she says several people claimed that "women couldn't go into space because we lacked the technology for them to pee in space."
It has all the info. on peeing and pooping outside the earth's orbit that you never knew you always wanted.