No, this isn't an astrology article. There are actual scientific studies that link birth month with various health conditions and personality traits. I'd heard before that birth month might be linked with rates of autism in children, but didn't realize that birth month has other implications until I read this fascinating LA Times article on the subject. Some examples:
People born in winter: Men with winter birth months may be more likely to be overweight, and both men and women are at increased risk of schizophrenia.
People born in spring: You are more likely to be tall than those born during other seasons, and may be at increased risk of multiple sclerosis.
People born in summer: You're more likely to be a night owl (not an early bird) and to be left-handed. Those with summer birth months may also be at increased risk of type 1 diabetes.
People born in fall: You seem to have a greater than average chance of reaching your 100th birthday, though children with fall birth months are at greater risk of food allergies.
The LA Times has more details on the studies, as well as interesting explanations for why these associations between health and birth month exist.