Gender segregation
Gender segregation is the reservation of areas or organisations that exclude either men or women. A high proportion of human societies have chosen some form of gender segregation and it is one of the biggest criticisms westerners often level at non-western societies.
Until 2020 the trend in Western nations was for men's spaces to be in decline and for women's spaces to be growing, producing one-sided gender segregation. This changed with the rise of the trans movement. From this point trans women entered women's spaces with impunity.
In recent years there is evidence that western civilisation may be adopting increased gender segregation but only when it excludes men. A lot of gender segregation in western countries is being driven by feminists who state that they often feel threatened by men, sometimes merely by their presence.[1][2]
This raises the interesting question about whether it was women who drove segregation in other societies. This would be interesting considering that gender segregation in non-western countries today is often claimed as principally disadvantaging women.
It may be reasonable for a society to permit gender segregation, but it must be on just and equal terms. Thus a society should permit both men's spaces and women's spaces only if they are available on equal terms. A society should allow both or it should allow neither. Until recently women in the West enjoyed uninterrupted access to women-only spaces and organisations while men were today largely prohibited from having men-only spaces and organisations. Since 2015 the rate at which trans women have successfully entered women's spaces has increased significiantly.