Health authorities in China have ordered probe to find whether children were used to test genetically modified (GM) rice in a project that involved researchers from China and US.
According to the China Daily, modified golden rice was tested on schoolchildren in Hunan province in 2008 as part of a Chinese-US research.
The health ministry asked the Chinese Center for Disease Control and Prevention (CDC) to find out the truth, and inform the public, a ministry spokesman said.
Yin said he was not aware of the GM rice test on children aged six to eight at a primary school in Hengyang, but confirmed that he did sign a notification from The American Journal of Clinical Nutrition to approve the paper's publication, China Daily reported.
The Chinese institutions or researchers involved claim they were unaware of the tests.
Environmental group Greenpeace broke the news of the controversial test in August, saying the joint research involved feeding the GM rice to 24 children. It cited a paper published in the August edition of the American journal.
According to China Daily, the paper claimed the golden rice - rich in beta-carotene - was effective in providing vitamin A to children.
It said the partners in the study were the Zhejiang Academy of Medical Sciences, Tufts University in the US, and the China CDC.
The Zhejiang Academy of Medical Sciences said it cooperated with Tufts University in 2004 on a study on beta-carotene, and its medical ethics panel had approved the study beforehand.
It said the programs the academy took part in did not involve GM rice, and that the academy had no idea if the study later tested GM rice on humans.