Women with summer birthdays tend to have fewer children than those born during other months of the year, according to an Austrian study published on Thursday.
Researchers who studied birth records of 3,000 Austrian women found that birthdays had an impact on reproduction and that females born between June and August had fewer children than other women.
“We found that the women born in July had 0.3 fewer children per woman than those born in December, or to put it another way, 13.4 percent fewer of the 2.24 mean number per women overall,” said Dr Susanne Huber of the University of Veterinary Medicine in Vienna.
She added that the findings, which are reported in the journal Human Reproduction, support the results of earlier studies of birth month and reproduction.
Huber and colleagues at the University of Vienna and the Medical University of Vienna do not know how birth month influences reproductive performance but they believe conditions early in life could be involved.
“In temperate zones the external environment varies with the seasons, so the conditions experienced early in life are the result of a variety of seasonally and socially varying environmental and maternal factors that may all affect early development, causing potential effects on later life events,” Huber wrote.
