Birth Season Affects Your Temperament Hungarian study says summer babies have more mood swings By Neal Colgrass, Newser Staff Posted Oct 20, 2014 2:50 PM CDT 26 comments Comments (Shutterstock) (Newser) – Getting moodier as you grow older? That may be because you were born in summer—assuming, of course, that you were born in summer, according to a new study out of Hungary. Researchers in Budapest who analyzed 400 people say they found a direct connection between the subjects' temperament and the season in which they were born, the Telegraph reports. To wit: People whose mood swung quickly and frequently from upbeat to sad (a "cyclothymic" temperament) were more likely born in summer. Those with a positive disposition (known as "hyperthymic") were more often spring or summer babies. Those born in fall have less chance of becoming depressive, while those born in winter are usually less irritable. Lead researcher Xenia Gonda of Semmelweis University tells CNET that environmental and genetic factors could be at play here. For example, she says, the season of birth may affect "what foods and nutrients are available [and] how much physical activity the mother had." The environment could also alter genetic factors, just as "seasonal affective disorder ... has been linked say to a polymorphism in the serotonin transporter gene." CNET, however, took a quick look at the birth dates of people considered temperamental—like Christian Bale and Ann Coulter—and found them to be winter babies. "Should we conclude that all these people were or are, in fact, not moody at all?" CNET asks.