Seasonal variation in human births
James, W.H.
Journal of Biosocial Science 22(1): 113-119
1990
ISSN/ISBN: 0021-9320 PMID: 2298756 DOI: 10.1017/s0021932000018423Document Number: 366282
During the first half of the century, the seasonal pattern of births in European countries showed a major peak in spring and a minor peak in autumn. Over the last 20 years the pattern in England, Wales and other European countries has changed to a US birth rate pattern which has only 1 broad peak from the summer to early fall. Many hypothesized factors may affect seasonal birth rates. A new hypothesis which expounds a festival effect of Thanksgiving to Christmas, where couples that are separated by work or choice often make time to be together and therefore improve coital frequencies is described. The magnitude of seasonality correlates positively with latitude: it is suggested that this is partially consequent on a variation in luminosity.