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China’s Health Ministry has ordered an investigation into claims that powdered baby milk caused girls — as young as four months old — to grow breasts.

The investigation by the country’s food safety authorities will look into allegations that three girls, aged between four and 15 months, were found to have abnormal premature pubescent developments allegedly after consuming the same baby formula. The infants, who live in three separate towns near the central Chinese city Wuhan, were reportedly found to have as much estradiol, a female sex hormone, in their tiny bodies as an adult woman. The babes also had three to seven times the expected level of another hormone called lactogen, an investigation by Beijing’s Health Times newspaper said. (See pictures of baby dictators.)

While the allegedly hormone-laced milk has, so far, only affected those three girls, it is eerily reminiscent of China’s tainted milk scandal in 2008 where at least six infants died and 300,000 were injured after being fed formula contaminated with the chemical melamine.

For their part, Synutra International Inc., the company that produces the milk powder, denied the claims. “We are completely confident that our products are safe and our quality levels are industry-leading,” said Liang Zhang, chairman and chief executive officer of Synutra told Bloomberg. Still, the company’s stock, which is listed on the NASDAQ, fell 27% — the largest drop for the company since 2008. (See pictures of babies during their first year of life.)

(Read: China’s Tainted Milk Scandal Grows).