STUDY: BIRTH OF TWINS LINKED TO POLLUTION

High levels of pollution may increase the rate of births of twins, a new study by German researchers suggests.

"The mothers of children in very polluted areas have had more twin births," said Nadia Obi-Osius, a member of a team from the Ministry of Environment and Health and the Institute for Medical Biometry and Epidemiology in Hamburg, Germany.

The researchers say the link between twins and pollution may reflect exposure to environmental factors that also could have effects on regulatory hormones or retardation.