The Chinese Centre for Disease Control and Prevention tested 42 samples of Synutra products and 31 samples of dairy products from other producers. Health Ministry spokesman Deng Haihua said that hormone levels were well within normal ranges in the sample products, with no hormones apparently added after the milk was manufactured.

However, parents want to know what products were tested and demand that a broader range of batches of milk powder be examined because they might vary in composition from place to place.

Many have also criticised the slow pace of government action, arguing that it could have allowed the company to change the composition of its milk powder products.

Wuhan resident Deng Xiaoyun told Radio Free Asia that even though her daughter’s “hormone levels have gone down a bit now"; she still wanted experts to explain why.

Synutra has gone on the offensive, claiming that allegations and arguments made by parents are “a media event” without scientific evidence to show that its products are responsible for the cases.

In an online statement, Synutra expressed sympathy for the families affected, but announced, “We intend to prosecute the parties responsible for these accusations to the furthest extent possible.”

In the meantime, some hospitals are full of infant girls with hormone levels equal or higher than those of adult women. Local media note that 30,000 children are in hospital in Shanghai alone for the problem, but claim that the "reasons are unclear."

One aspect of the problem is that many baby girls have begun to develop breasts.

Many parents are also upset that endocrinology departments in hospitals are examining just a few cases every day, at a rate that is woefully inadequate to address all the cases, a situation found in many cities.

This crisis comes in the wake of another baby formula scandal, which broke out in 2008, involving a chemical substance, melamine, that is highly toxic to humans and that was added to milk powder in order to boost its protein content.

At least six deaths were recorded out of 300,000 children who became ill with kidney problems.