A prominent U.S. panel of scientists has concluded that not enough is known about hormone-altering chemicals to calculate their risks to humans. In a report requested by Congress, a committee of the National Academy of Sciences yesterday acknowledged that pesticides and other chemicals that mimic estrogen and block male hormones seem to be feminizing some wildlife, as well as suppressing animals’ immune systems and causing neurological damage. But the 16 scientists, including two who work for chemical companies and several viewed favorably by environmentalists, said there was too little data to conclude whether the ubiquitous, hormone-mimicking chemicals are harming people too. The panel called for more research.