ADELAIDE, Australia, April 30 (UPI) -- Human male fetuses grow at a different rate than female fetuses when the pregnant mother is under stress, scientists in Australia said.
"The male, when the mum is stressed, pretends it's not happening and keeps growing, so he can be as big as he possibly can be," researcher Vicki Clifton of the University of Adelaide said.
The female, in response to the mother's stress, will reduce her growth rate, but not so much that it restricts growth, Clifton said in a release from the university Thursday.
"When there is another complication in the pregnancy –- either a different stress or the same one again -- the female will continue to grow on that same pathway and do OK but the male baby doesn't do so well and is at greater risk of pre-term delivery, stopping growing or dying in the uterus," Clifton said.
The difference in growth response was seen in pregnancies complicated by asthma, cigarette use and psychological stress, Clifton and her team said.
