US company Wyeth said it had received complaints that children who had been fed its baby milk powder in China had developed kidney stones, but denied its products were unsafe. The statement posted on Wyeth's China website on Monday was the latest in a rash of reports of sick babies that is raising new concerns long after a tainted baby formula scandal was declared over by Chinese authorities. Authorities this month investigated the domestically produced milk powder of Danone Dumex, a unit of French food giant Danone, after similar consumer allegations. China's product-quality regulator later cleared Danone, although the health ministry said last week it was investigating why children may be suffering kidney problems if not through tainted milk.