近亲结婚未必导致下一代先天性疾病

　　In the U.S., though, the practice bears a stigma of inbreeding just this side of incest. The taboo is not only social but legislative; 24 states ban the marriage of first cousins: five others allow it only if the couple is unable to bear children. A major reason for this ban is the belief that kids of first cousins are tragically susceptible to serious congenital illnesses.

　　然而在美国，同宗结亲的做法仍带有近亲繁殖的耻辱，并有乱伦之嫌。这种禁忌不仅是社会习俗方面的，而且有来自立法机关的：有24个州禁止近亲结婚；其他5个州只有在一对夫妻不育的条件下才许可。颁布此禁令的一个主要原因是人们相信近亲结婚易导致下一代不幸地患上严重的先天性疾病。

　　That view may have to change. A comprehensive study published recently in the Journal of Genetic Counseling indicates such children run an only slightly higher risk of significant genetic disorders like congenital heart defects--about two percentage points above the average 3% to 4%. Says the study's lead author, Robin Bennett, president-elect of the National Society of Genetic Counselors, which funded the study: "Aside from a thorough medical family history, there is no need to offer any genetic testing on the basis of consanguinity alone".

　　这种观点可能必须改变。最近发表在《遗传学咨询》杂志上的一份综合性研究表明近亲婚姻所生的小孩患上主要遗传性疾病如先天性心脏缺陷的可能性只比一般小孩略高--大约比平均的3%到4%高出两个百分点。全国遗传学顾问协会为此项研究提供了资金。罗宾-贝内特是此项研究的主要作者，也是该协会已当选、但尚未就职的主席。据他说，“除了需要一份详尽的家庭病史之外，没有必要仅根据有血缘关系这一条理由就进行任何的基因测试。”

　　Publication of the study will do more than tweak public awareness; it will enlighten doctors who have urged cousin couples not to have children."Just this week," says Bennett， "I saw a 23-year-old woman who had had a tubal ligation because her parents were cousins and her doctor told her she shouldn' t have children." The study cites the case of" Amy," who had been in a relationship with her cousin for two years when, in 1996, she became pregnant. Her doctor suggested an abortion, and after a fruitless search for more information, she had the procedure. This week Amy wrote to the cousincouples.com website that she planned to get many copies of the report--"one that I will personally deliver to my ex-gynecologist."