填空题 Women who are stressed while trying 1 are more likely to have girls, research suggests.
A study found that those who were under pressure 2 , work or in their love life in the weeks or months before becoming 3 had higher than usual odds of giving birth to a daughter 4 a son.
The finding, by Oxford University and U.S. researchers, 5 the economic downturn could see more women give birth to 6 . The study follows others that have shown 7 goes down following major upheavals.
For instance, in the months after the 9.11 8 , the number of boys born in New York plunged, while the economic chaos 9 followed the collapse of the Berlin Wall saw far fewer boys born 10 in the former East Germany in 1991.
But the latest study is the first 11 to the stresses and strains of everyday life and to rising levels of stress hormones.
12 from around the U.K. who were trying to get pregnant kept diaries about their lives and 13 about how stressed they felt. Levels of stress hormones including cortisol were measured 14 before pregnancy.
Among the 15 of the women who had the highest amounts of cortisol 16 , the sex ratio was clearly skewed towards girls, the American Society for Reproductive Medicine"s annual conference heard.
The most stressed women were up to 17 to have boys than the least stressed, the conference in Orlando, Florida, 18 . Cortisol levels rise when people suffer long-term stress such as pressure at work and bad relationships.
It isn"t known why 19 cortisol appear to cut the odds of having a boy.
But, if the link is firmed up, 20 may be told about the benefits of relaxation, in the same way as they are now advised to take care of their health in other ways.