Haven't found a way to change ratios, but if all you are trying to do is remove female soldiers from the game there is a way to do it but it is a bit of a hack. Well I guess in the code they are still considered female so think of them more like post-op trannies taking hormones to make their voices drop and facial hair grow
Of course you could always just dismiss the lady soldiers but then you lose half of your starting squad and the associated stat bonus they come with. Maybe that is the price you pay?
The half and half male/female squad mix does not bother me much it just doesn't seem realistic or at least historically accurate for 1979. I'm all for equality of the sexes and if Xenonauts were set in the future it would be more plausible. For me I would just like to be able to change the ratio of male to female to about 3/1 which is probably generous for worldwide armed forces circa 1979.
I have mixed feelings about removing the female soldiers from the game- for instance I probably wouldn't feel inclined to help someone who asked to remove all black soldiers, or all blue eyed soldiers etc.