Before revision: According to the Oxford English Dictionary, gender came into use as a synonym for sex during the twentieth century, initially as a euphemism, because sex was undergoing its own usage shift toward referring to sexual intercourse rather than male/female categories.
After revision: According to the Oxford English Dictionary, gender came into use as a synonym for sex during the twentieth century, initially as a euphemism, as sex was undergoing its own usage shift toward referring to sexual intercourse rather than male/female categories.