[ti:Study Suggest Genetic Connection to Same-sex Behavior, But Not to Genes] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.01]A large study suggests that genes are connected to homosexual behavior, [00:07.59]but also found there is no gene that makes people gay. [00:13.18]The study is said to be the largest of its kind. [00:18.11]Researchers examined genetic material and information about sexual experiences [00:25.93]from more than 470,000 adults in the United States and Britain. [00:33.20]The findings were published in Science magazine. [00:37.61]The researchers found there are thousands of genetic differences linked to same-sex sexual behavior. [00:46.92]Most have a very small effect on a person's behavior. [00:51.47]However, the researchers said five of the genetic markers [00:57.86]were more strongly linked with same-sex sexual behavior. [01:03.66]The genetic differences, or variants, were more commonly found in people [01:10.93]who reported having had a same-sex sexual experience at some time. [01:18.52]Some of the genetic variants found were present in both men and women. [01:25.89]Two of the variants found in men were near genes involved in male hair loss and sense of smell. [01:36.23]About five percent of British participants and about 19 percent of U.S. persons [01:43.82]who took part reported ever having a same-sex sexual experience. [01:50.18]Those providing information for the study were not asked [01:55.48]whether they identified themselves as gay or lesbian. [02:00.96]The research "provides the clearest glimpse yet" into the genetic reasons [02:07.55]for same-sex sexual behavior, said study co-writer Benjamin Neale. [02:14.07]He is a geneticist at the Broad Institute in Cambridge, Massachusetts. [02:19.93]But Neale also added, "We also found that it's effectively impossible [02:26.94]to predict an individual's sexual behavior from their genome." [02:33.39]The researchers noted that the study centered on people's sexual behavior, and not on sexual identity. [02:42.82]They also noted that the study only involved people whose ancestors were European. [02:49.88]They could not answer whether similar results would be found in other groups. [02:56.73]The origins of same-sex behavior are unclear. [03:02.35]Some of the strongest evidence of a genetic link comes from studies on twins. [03:09.48]Many scientists believe that social, cultural, family and biological conditions are also involved. [03:19.58]Some religious groups and other critics consider it a choice or a behavior that can be changed. [03:28.56]A Science magazine commentary notes that the five identified genetic variants [03:36.16]had such a weak effect on behavior that using the results [03:40.94]"for prediction, intervention or a supposed ‘cure' is wholly...impossible." [03:48.53]Experts not involved in the study had many reactions. [03:53.57]Former National Institutes of Health geneticist Dean Hamer said the study [04:01.26]confirms "that sexuality is complex and there are a lot of genes involved." [04:08.73]But he added that the study was not "really about gay people." [04:13.80]"Having just a single same sex experience is completely different than actually being gay or lesbian," Hamer noted. [04:24.36]His research in the 1990s linked a marker on the X chromosome with male homosexuality. [04:33.79]Later studies had similar results. The latest study, however, found no such link. [04:41.85]Doug Vanderlaan is a psychologist at the University of Toronto in Canada. [04:49.25]He said the lack of information on sexual orientation is a weakness of the study. [04:57.06]The study was released on August 29. [05:01.68]An international team of experts from Britain, the U.S., Europe and Australia carried out the research. [05:10.69]They completed human genome examinations using blood samples from the UK Biobank [05:19.42]and saliva samples from the U.S.-based ancestry company 23andMe. [05:26.57]All samples were from individuals who had agreed to take part in the research. [05:33.23]I'm Anna Mateo. 更多听力请访问51VOA.COM