Two years ago, news headlines began to appear about a development that made many human geneticists uneasy. A U.S. company planned to offer a test for embryos created through in vitro fertilization (IVF) that screened the entire genome for DNA variants linked to cognitive ability, in order to help couples avoid having children with intellectual impairment. Many ethicists fear such multigene analyses could one day be used to screen embryos for desirable traits as well, such as tall stature or high IQ.
For those disturbed by the prospect, a study reported here last week at the annual meeting of the American Society of Human Genetics (ASHG) may come as a relief: For now, the strategy would not work very well.
Researchers, led by statistical geneticist Shai Carmi of the Hebrew University of Jerusalem, calculated exactly how much of a boost in IQ or height could be expected by scanning for relevant DNA markers in a batch of embryos and choosing those with the highest scores. The result: The gains would be slight, and prospective parents might even end up discarding... see more