The people of the Aamjiwnaang First Nation are concerned that exposure to a notorious cluster of chemical plants is severely influencing birth rates. A review of birth records found there aren't very many boys being born in the southwestern Ontario community, and the number is dropping.

According to a study published in the American journal Environmental Health Perspectives, only about a third of babies born on the reserve between 1999 and 2003 were male. Going back to include another five years, only 41 per cent of babies born in the decade were boys. The ratio is normally something closer to 50:50.

Residents of the 850-member Chemical Valley native group started asking questions in 2003 when they realized there were three all-girl softball teams and only one for boys.

"Is it what we're breathing in on a daily basis? Is it where we played as kids? Is it something our parents did? Is it these small exposures or is it because we've been living here our whole lives?" asked Ada Lockridge, a member of the band's environmental committee.

The Sarnia area is home to Canada's largest cluster of chemical, allied manufacturing and research and development facilities. Out of the 10 largest chemical companies in the world, eight have operations in Ontario.