The New York Times has an article here on the stigma that single women face in Korea. For those who chose to become mothers outside of marriage, the social pressure can be significant.
[E]ach year, social pressure drives thousands of unmarried women to choose between abortion, which is illegal but rampant, and adoption, which is considered socially shameful but is encouraged by the government. The few women who decide to raise a child alone risk a life of poverty and disgrace.
Thanks to Nancy Kim for pointing out this article.