BBC随身英语:The three-parent kid 有三个父母的孩子

The role of parents is not only to give us love and guidance, but also to pass on genetic code.

A few particular healthy genes would be the contribution of the third parent, according to a British government decision to support a ground-breaking technique for preventing genetic disease.

It has to do with the mitochondria, the energy factory we have in our cells. They contain just 37 genes and sit outside the nucleus which has more than 20,000 genes. Diseases caused by faulty mitochondria are serious and are passed down the maternal line in the egg, so the technique being pioneered by Newcastle University involves using healthy donor eggs.

After fertilisation, the genes of the father and the mother would be transferred from the embryo to the healthy donor egg, which has had the genetic material from its nucleus removed but still has good mitochondria.

To explain the technique, scientists in Newcastle compared it to changing the battery of a laptop computer. Like in the hard-drive, nothing changes in the DNA of the two parents because they are in the nucleus.

The government will prepare regulations later this year and the technique could be available within two years. Faulty mitochondria affect one in every 6,500 babies and it can cause lack of energy and result in muscle weakness, blindness and heart failure.

Some people are opposed to this because they consider it unethical and say it could set the UK on a slippery slope. The nightmare of creating a Frankenstein's monster is always in our mind. They also say that couples with the problem could adopt a child instead.

But the same was said when the world's first test tube baby, Louise Brown, was born in Britain in 1978. And the only Frankenstein we see is in the movies.

The fact is that families are changing all the time. Who knows what the typical family will be like in 50 years' time...

Quiz 测验 1. What's the purpose of the new technique?

It was developed to prevent genetic diseases caused by faulty mitochondria.

2. What did scientists in Newcastle compare it to?

To changing the battery of a laptop computer.

3. How can faulty mitochondria affect a person?

It can lead to muscle weakness, blindness and heart failure.

4. Was Louise Brown born with three genetic parents?

No. She was born in 1978 and the three-parent technique is being developed now.

5. Name four elements of a cell mentioned in the article.

Genes, nucleus, mitochondria, DNA.

Glossary 词汇表 the more the merrier越多越好 the genetic code遗传密码 a gene基因 ground-breaking突破性的，具有开创性的 genetic遗传的 mitochondria (plural)线粒体（复数） a cell细胞 the nucleus (of a cell)细胞核 maternal line母系 to pioneer开创，倡导 a donor egg捐赠的卵子 fertilisation受精 an embryo胚胎 the hard-drive硬盘 DNA脱氧核糖核酸 the regulations规章制度，条例 muscle weakness肌无力 unethical不合乎道德准则的 a slippery slope滑坡，难以阻止、控制的困境 to adopt (a child)领养（一个孩子） a test tube baby试管婴儿