Around 1973-75 the period I was relating it was definately only male cabin crew on the freighters. I think it started to change around 1975 when the equality laws etc all changed.
I enjoyed working the freighters apart from the fact that at many destinations-you would stay in different hotels to the flight deck crew-so would sometimes be on your own for a day or two-which for me was no problem anyway.
Some of the more sociable crews would invite you to join them for dinner etc anyway.
I recall carrying a White Rhino and a handler from I think Hong Kong to Delhi or another Indian city .?