<font class="UCASE">imbalances</font> in sex ratio around the world have been attributed to a variety of reasons. Scientists have now found more evidence of a link between chemicals like polychlorobiphenyls (<font class="UCASE">pcb</font>) and a decline in the birth of males.<br><br> Over the years scientists and communities have descerned a peculiar trend. The Aamjiwnaang community near Sarnia in Canada have, for example, voiced concerns over the declining male population in the community. Their observation was confirmed in a study by Ottawa University in 2005.<br>