Summer apparently could be the best time to be born. But how true is it? That depends on what traits you consider to be most advantageous. Although a recent study found that baby girls born in June, July, and August develop into healthier women than girls born at other times of the year, past medical research has also linked summer birthdays to those who have less successful career outcomes.
For a recent study, now published in the online journal Heliyon, researchers from Cambridge University in the UK investigated an idea that has fascinated humans: Can a child’s birthday give clues to their future? While we have often looked to the stars for this answer, the Cambridge team went to science instead.
“When you were conceived and born occurs largely ‘at random’ — it’s not affected by social class, your parents’ ages, or their health — so looking for patterns with birth month is a powerful study design to identify influences of the environment before birth,” said lead author Dr. John Perry in a statement.
Results revealed that girls born in the summer were slightly heavier at birth, taller as adults, and went through puberty slightly later than those born in winter months which means good health. The team hypothesized differences in the later life health of summer and winter babies may be caused by the amount of sun that their mothers received during their pregnancy — a factor that significantly determines her vitamin D exposure. However, the researchers insisted that, at this point, they are still unsure why this happens.
“We need to understand these mechanisms before our findings can be translated into health benefits,” Perry added.
Previous research, however, has revealed less advantageous effects of summer birthdays. According to a 2012 study published in Economic Letter, individuals born in summer months are the far less likely to hold CEO positions than individuals born in other times of the year. The reason for this was more simple: In many schools, the cut-off date for registration falls between September and January. This leaves those with summer birthdays as the youngest in their grade. Maurice Levi, the study’s co-author said that older children within the same grade tend to do better than the youngest. These career outcomes may be the result of early successes in school.