PsychBriefs: September 16-22, 2007

Stressed Women More Likely to Birth Girls
A study of 6000 infants and mothers shows that pregnant women with high stress levels are five percent more likely to have girls than relaxed mothers. Researchers suggest that high levels of stress hormones may make it more likely that male embryos fail to implant or that male fetuses miscarry. Previous studies have shown that smoking likewise lowers the number of males born.
[ABSTRACT][ARTICLE]

Gene May Make Some Infants More Vulnerable to Fetal Alcohol Syndrome
A study on Rhesus monkeys suggests that carriers of the short allele of a gene called a serotonin transporter gene promoter are at a greater risk for suffering damage caused by moderate in utero alcohol use. The findings may help explain while the children of some human mothers experience birth defects due to their mothers' alcohol consumption and others do not.
[ABSTRACT][ARTICLE]

Attraction Gauged in Half a Second
A new study on attraction shows it only takes half a second to identify someone attractive enough to be a potential mate--or to be a threat to your current relationship. A series of three experiments found this was true for both male and female participants. However those in the study who were in committed heterosexual relationships focused more on members of the same sex, suggesting that once we've found a partner, we start sizing up the competition. Singletons, meanwhile, held their gaze on attractive members of the opposite sex.
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