"It may sound like some kind of new, madcap astrology, but several scientists are becoming convinced that our birth month may predispose us to particular diseases.
Studies have shown that schizophrenia is more common among those born in late winter or early spring. Multiple sclerosis is associated with births in April, May and June. And epilepsy occurs more frequently in those with birthdays from December to March.
...adults born in January and February had the highest risk of brain cancer. Those with birthdays in July and August had the lowest risk."
http://seattletimes.nwsource.com/cgi-bin/PrintStory.pl?document_id=2002011657&zsection_id=268448413&slug=birthmonth21&date=20040821