Having children is costly, and there are other factors besides that. Reproductive system problems have arisen due to a lack of nutrition and exercise. Some people have to pay several years' worth of salaries for treatment. Furthermore, people want to spend the time they spend raising children on themselves. In the past, marriage was necessary to have sex. Nowadays, people can marry without having sex. Technology makes it much easier.

Nowadays, people believe they can live without needing anyone else. It makes more sense for them to live a life without getting married.