While this may be true for capsule missions, technology has advanced somewhat, so that astronauts traveling on the Space Shuttle now have an actual toilet available to them. Although it has been the butt (ahem) of many jokes, it must be considered a massive improvement over diapers and catheters, Texas or not. :-)

I would presume that the facilities on the ISS (and Mir, and Skylab) were also more advanced and consequently more comfortable to use. They are, of necessity, unisex.