In China, HIV-positive rural or ethnic minority women often are unaware of their rights under the law, a study backed by the UN has found.

The root cause is illiteracy, said researcher Bu Wei, a professor with the Chinese Academy of Social Sciences.

"They don't know how to protect themselves with laws and what rights they are entitled to," Bu said.

In a population of 1.3 billion, China has an estimated 740,000 people with HIV. The proportion of women in China's HIV-positive population rose from one-sixth in the 1990s to one-third in 2007. In 2004, women represented 55 percent of those who contracted the disease through sexual transmission, up from 44 percent in 2001.

Bu's study consisted of interviews with 857 individuals, 80 percent of whom were women. It was conducted by the Chinese Academy of Social Sciences and backed by UNAIDS and the UN Development Fund for Women.

The study recommends short-term strategies to empower women, such as providing literacy education and information about HIV/AIDS. It also recommends broader economic responses, such as assisting women in applying for micro-financing.

The study will be revised to include more specific and policy-directed recommendations, Bu said.