| 1. | Bob james , a professor in the dairy science department at virginia tech and heldreth ' s former teacher , said such births are unusual . " in my 25 years , i ' ve seen it maybe two or three times , but it ' s pretty rare , " he said . james said the abnormality could be caused by a developmental problem or a genetic quirk . according to medicinenet . com , the condition is called diprosopus 弗吉尼亚州技术学校奶牛科学部的教授詹姆斯表示,这样的“双面”牛很罕见。他说: “ 25年来,我只见过两三例这样的情况,这的确不多见。 ”詹姆斯指出,这种双面畸形在医学上被称作“双面畸胎” ,它是因双胞胎在发育过程中未完全分离所致。 |