Yang Xiuhua, a middle school principal in Guyuan city, Northwest China's Ningxia Hui autonomous region, chose to greet her students on Tuesday with a pep talk.

Located in Xihaigu in Ningxia, an area declared "uninhabitable" by the UN World Food Programme, the school educates students from poor rural households where children are living alone or with their grandparents.

The care they receive from the dedicated educator has had a life-changing impact on the students. For over a decade, Yang has been teaching "left-behind" children to understand their self-worth. The school also provides extracurricular lectures on sex education, including necessary knowledge of personal physiological hygiene and mental health.

"Some day, the students will become parents. And I hope the proper understanding of sex and the concept of their own self-worth will be passed on through generations," the principal said.