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.