Single-sex education, also known as single-gender education and gender-isolated education, is the practice of conducting education with male and female students attending separate classes, perhaps in separate buildings or schools. The practice of single-sex schooling was common before the 20th century, particularly in secondary and higher education. Single-sex education is practiced in many parts of the world based on tradition and religion. Recently, there has been a surge of interest and the establishment of single-sex schools due to educational research. Single-sex education is practiced in many Muslim majority countries; while in other parts of the world it is most popular in Chile, Israel, South Korea, and English-speaking countries such as Singapore, Ireland, the United Kingdom, Hong Kong, New Zealand, South Africa and Australia. In the Western world, single-sex education is primarily associated with the private sector, with the public (state) sector being overwhelmingly mixed sex; while in the Muslim world public schools and private schools are sex-segregated. Motivations for single-sex education range from religious ideas of sex segregation to beliefs that the sexes learn and behave differently. As such, they thrive in a single-sex environment. In the 19th century, in Western countries, single-sex girls' finishing schools, and women's colleges offered women a chance of education at a time when they were denied access to mainstream educational institutions. The former was especially common in Switzerland, the latter in the U.S. and the U.K., pioneers in women's education.