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Sept. 21 (UPI) -- Mommy gene may explain birth rate KINGSTON, Ontario, Sept. 21 (UPI) -- A Canadian researcher suggests a "mommy" gene may explain the increasing number of women who decide against having children.

Lonnie Aarssen, a biology professor who specializes in reproductive ecology at Queen's University in Kingston, Ontario, said basic principles of biology rather than women's newfound economic independence may explain the declining marriage and birth rate in developed countries.

"Only in recent times have women acquired significant control over their own fertility, and many are preferring not to be saddled with the burden of raising children," Aarssen said Friday in a news release.

The report, published in the current issue of the ecology journal Oikos, suggests inherited inclinations lead some women to pursue leisure and other personal goals that distract from parenthood.

"The drive to leave a legacy through offspring can be side-tracked by an attraction to legacy through other things like career, fame, and fortune -- distractions that, until recently, were only widely available to men," he said.

He speculated the trend will eventually subside because, over time, genetic traits influencing women away from motherhood will necessarily be "bred out."

Arctic ice melt largest on record BOULDER, Colo., Sept. 21 (UPI) -- U.S. scientists said the amount of sea ice that melted in the Arctic this summer has shattered all previous records.

The University of Colorado at Boulder's National Snow and Ice Data Center said Arctic sea ice on Sept. 16 stood at 1.59 million square miles, about 1 million square miles less than the long-term minimum average from 1979 to 2000. Scientists compared the loss to an area about the size of Alaska and Texas combined.

The sea ice is at its lowest level since satellite record-keeping began nearly 30 years ago, the university said Friday in a release.

Scientists blame the declining Arctic sea ice on rising concentrations of greenhouse gases that have increased temperatures from 2 to 7 degrees Fahrenheit across the arctic and strong natural variability in Arctic sea ice, the researchers said in a release.

Arctic sea ice melts each summer, reaching its minimum extent in September and it is usually at maximum area in March.

The researchers used satellite data from NASA, the National Oceanic and Atmospheric Administration and the U.S. Department of Defense, as well as data from Canadian satellites and weather observatories for the study.

Drought not drying out Amazon PHOENIX, Sept. 21 (UPI) -- U.S. and Brazilian researchers say the Amazon forest was surprisingly unaffected by a 2005 drought.

Scott Saleska of The University of Arizona said the finding contradicts a prominent global climate model that predicted the Amazon forest would eventually collapse as the drought progressed. The findings, based on data from two National Aeronautics and Space Administration satellites, were published online in the current issue of Science Express.

During the 2005 drought, Amazon forest trees flourished in the sunnier-than-average weather, most likely by tapping water deep in the forest soil. In many areas, the canopy of the undisturbed forest became significantly greener, the report said.

Saleska said that from an evolutionary standpoint, the resilience of the forest in a single drought year makes sense. During El Nino, which occurs about every four to eight years, the Amazon forest receives significantly less rain than average.

Saleska said forest's resiliency, however, is not limitless.

"But if you take away enough water for long enough, the trees will die," Saleska said Friday in a release.

Research suggests fetal alcohol gene MADISON, Wis., Sept. 21 (UPI) -- U.S. and Canadian researchers say a gene variant may make some infants more vulnerable to brain damage from fetal alcohol exposure.

The report, published in the journal Biological Psychiatry, said a genetic marker that signals susceptibility could provide a way of recognizing children most vulnerable to fetal alcohol damage, and find ways to help them overcome their problems, lead author Mary Schneider of the University of Wisconsin-Madison said Friday in a release.

Primates were used in studies of a gene called a serotonin transporter gene promoter, which helps regulate the brain chemical serotonin. Past studies of both people and primates suggest that carriers of a short form of this gene are at increased risk for depression.

The researchers found that primates who carried the short gene also suffered problems from exposure to moderate levels of alcohol in utero, the report said.

Schneider said the finding may help to explain why some children of mothers who drink during pregnancy suffer birth defects, while others seem to escape unharmed.

Copyright 2007 by United Press International

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