Chinese baby girls between the ages of 15 months and four years old have reportedly developed breasts after drinking milk formula.

The China Daily newspaper says three children were tested and found to have hormone levels greater than adult women.

Hubei Maternity and Children's Hospital chief physician Yan Qin said "parents should stop using the formula to feed their children and that the powder needs to be analysed".

The Qingdao-based company Synutra, which produces the powder in question, says its products are safe.

Some have speculated that hormones may have entered the food chain earlier because farmers are feeding them to cows.

The practice is not against the law in China.