《英语流行话题阅读:语境识词3500》Unit88:连体婴儿

　　Unit 88
Siamese Twins
Siamese twins are formed from a single egg which develops into two almost separate parts of cells. Normally, each part becomes an identical twin. However, cells in Siamese twins become confused about where they are in the body -- indeed which of the two Siamese twins they are actually in.
In normal fetus¹ development every cell knows where it is in the body because the neighboring cells produce chemical messages. So a skin cell knows not only it is skin, but that it is, say, nose skin, rather than chin or ear or lip skin. In Siamese twins these chemical messages don't work properly -- ho can they? The end results can be very odd: a single organism with two heads, tow hearts, four legs and arms -- or is that single organism actually two people, two individual Siamese twins?
Although at first sight each appeared to have a separate well-formed body with some joining at the lower body, detailed² tests showed these Siamese twins were very unequal. In some cases, one was providing the heart, lungs and many other basic functions. The other Siamese twin was vey poorly equipped for separate life. To make matters worse, these Siamese twins were to some extent dependent on each other. If separated, the stronger and more capable Siamese twin would need huge amounts of surgery over the following years, and was likely to suffer significant handicap.
It is a brave doctor indeed who is willing to take the knife to two Siamese twins, both of which are at that point alive and growing, and see perhaps both Siamese twins die in the operating room or very shortly afterwards. It is easier to go ahead if the parents want their Siamese twins separated and understand and accept the risks -- but what if you have had to force the whole thing on them in the first place? A key Problem in Siamese twin decisions is that the parents themselves may no always agree on the separation, and it is common for them to feel somehow that the birth of Siamese twins is their fault, or to blame each other, doctors, society or God. The natural joy of birth has been replaced by deep grief for the loss of one or two perfectly³ normal children.
And there is another issue. The survivor⁴ of these Siamese twins would need huge care efforts. This would be unlikely in some cultures and parents may feel very angry at medical interference.
On balance, doctors should tread with great care when it is a human right and the responsibility for parents to make decisions on behalf of their children to refuse certain medical treatment.

1 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

2 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

3 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

4 survivor   

n.生存者，残存者，幸存者

参考例句：

• The sole survivor of the crash was an infant.这次撞车的惟一幸存者是一个婴儿。
• There was only one survivor of the plane crash.这次飞机失事中只有一名幸存者。