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Despite folklore, it appears that a woman’s body shape does not predict the gender of her children. Some cultures believe that a curvy body shape in mothers is more likely to lead to the birth of girls, and a more androgynous body shape boys. A study at the University of Minnesota and the University of Newcastle in England measured the waist and hips in women planning to have children, then tracked their subsequent offspring. No significant correlation was discovered in the 458 women studied. Previous studies have suggested a link, but they typically measured the waist-hip ratio after childbirth and then compared it with the genders of existing children. Those findings may be explained by changes in the body caused by carrying more male children, who are normally larger and heavier. The new study was published in the May 22, 2001, issue of the Proceedings of the Royal Society of London (www.pubs.royalsoc.ac.uk/proc_bio/proc_bio.html).

Add the ability to absorb atmospheric carbon dioxide and nitrogen (two substances linked to global climate changes) to the list of reasons to preserve biodiversity. A study led by University of Minnesota forest resources professor Peter Reich has found that a prairie ecosystem with a wide array of plants can better use carbon dioxide and nitrogen than one with relatively few plant species. Yet human activity (through croplands, lawns and gardens, and commercial tree stands, for example) is shaping ecosystems to contain fewer species of plants at a time when levels of atmospheric carbon dioxide and nitrogen are on the rise. The study, conducted at the University’s Cedar Creek Natural History Area north of the Twin Cities, involved setting up 296 open-air plots with one, four, nine, or 16 prairie plant species. Some plots were grown with extra carbon dioxide and some with both more carbon dioxide and nitrogen. Those with more diversity of species were consistently better at absorbing the elements as measured by increases in biomass, which is about half carbon. In areas with added carbon dioxide, 16-plant plots added biomass at three times the rate of single-species plots when compared with control plots. With combined carbon dioxide and nitrogen, the advantage was about double. Reich theorizes that diverse mixes of plants are likely to contain species with a range of ways to utilize the nutrients and are more likely to contain species that help each other’s synthesis. The work was published in the April 12 issue of Nature (www.nature.com/nature).

Despite controversy over the use of standardized college admissions tests, University of Minnesota analyses of two of the most popular measures, the Scholastic Aptitude Test (SAT) and the Graduate Records Examination (GRE), show them to be generally strong predictors of college success. Colleges widely employ the SAT in reviewing undergraduate admissions applications. The GRE comprises both a standard test and several subject tests used for graduate school admissions. Both studies analyzed more than 1,500 previously published reviews of the tests, with the GRE study involving more than 82,000 students and the SAT study more than 1 million.

The SAT analysis looked at various sizes and types of colleges and found that test scores are a strong predictor of first-year grades: The higher the SAT score, the better the grades. That influence continues in subsequent years and extends to success in completing a degree. The study also found that the correlation to first-year grades remains consistent for different gender and racial groups. The research was presented at an April meeting of the Society for Industrial and Organizational Psychology and may be submitted for publication in fall. The study was funded by the College Board, a consortium of colleges that administers the SAT and offers other college entrance services, in order to get a definitive answer on their validity.

The GRE study found a correlation between GRE scores and grad-school grades, faculty ratings, success in getting the graduate degree, research success, and other measures. One area the GRE did not measure well was how long it took to finish an advanced degree. The study’s lead author, psychology doctoral student Nathan Kuncel, who also was part of the SAT analysis, said undergraduate faculty ratings and personal history are more likely to accurately predict timely degree completion. The GRE research is published in the January 2001 issue of the Psychological Bulletin (www.apa.org/journals/bul.html).