1)Conjoined Twins

By Nancy Steinbach

Broadcast: October 29, 2003

This is Faith Lapidus with the VOA Special English Health Report.
Some estimates say that one in as many as eighty-thousand of all births results in two babies joined together. Conjoined twins happen about once out of every two-hundred births of identical twins.
Some twins develop from two separate eggs that are 2)fertilized² at the same time. These babies are called 3)fraternal twins. One can be a girl and the other a boy.
Other twins develop from a single egg. These are called identical twins. Identical twins result when a fertilized egg divides into two.
Sometimes the division begins but is not completed. This produces twins who are physically³ linked. Medical experts say genetic⁴ and environmental influences are involved in the development of conjoined twins.
Recent separations have taken place in Britain, Singapore, Italy, Australia and the United States. These included an operation where doctors at the Children's Medical Center in Dallas, Texas, separated two Egyptian boys joined at the head.
Conjoined twins may be linked only by a thin piece of 4)tissue. Or they may be attached at the chest or other part of the body. Sometimes they share a heart or other internal organ.
In the past, conjoined twins were called 5)Siamese twins. This was because the first well-known twins were born in Siam, the country now called Thailand. Chang and Eng were born in eighteen-eleven. A twelve-centimeter-long ligament near their breastbones connected them. Chang and Eng grew up, married and had a total of twenty-one children. The two men died in eighteen-seventy-four.
Historically, the survival rate for conjoined babies has been between five and twenty-five percent. But medical progress has increased those chances.
Today, most conjoined twins are found during examinations before they are born. Some are easier to separate than others.
The book "Entwined Lives" by Nancy Segal says doctors have performed about two-hundred operations to separate conjoined twins. Ninety percent have taken place since nineteen-fifty. The book says most of the operations resulted in the survival of at least one of the babies.
One Web site where you can learn more about conjoined twins is twinstuff-dot-com.
This VOA Special English Health Report was written by Nancy Steinbach. This is Faith Lapidus.

注释：
1) conjoined Twins  连体双胞胎
2) fertilize¹ [5f\:tIlaIz] vt.使受精
3) fraternal twins  异卵双生
4) tissue [5tisju:] n. （生）组织
5) Siamese twins  n.暹罗双胎, 连体婴

1 fertilize   

v.使受精，施肥于，使肥沃

参考例句：

• Fertilizer is a substance put on land to fertilize it.肥料是施在地里使之肥沃的物质。
• Reading will fertilize his vocabulary.阅读会丰富他的词汇。

2 Fertilized   

v.施肥( fertilize的过去式和过去分词 )

参考例句：

• The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
• Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。

3 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。