Popular theories are favoured about the lack of women in computer science, which discount historical and social circumstances. In 1992, John Gray's "Men Are from Mars, Women Are from Venus" theorised that men and women tend to differ in ways of thinking, leading to them approaching technology and computing in different ways. A significant issue is that women find themselves working in an environment that is largely unpleasant, so they decline to continue in those careers. A further issue is that if a class of computer scientists contains few women, those few can be singled out, leading to isolation and feelings of non-belonging, which can culminate in leaving the area.