雅思阅读材料：父亲年龄大孩子长得丑

　　研究发现，父亲年龄大的孩子相貌也较丑，但是这些丑孩子的寿命却会比其他人长。

　　研究指出，45岁以上的男人生出的孩子患自闭症和精神疾病的风险比其他孩子更高。父亲年龄越大，基因突变的概率也会成倍增加。

　　相比之下，母亲遗传给孩子的基因最多只会发生15个突变，不管母亲年龄多大。

　　科学家称，22岁的父亲生出的孩子比40岁的父亲生出的孩子相貌水平要高出5%到10%。

　　Older fathers have uglier children, researchers have claimed after linking age to genetic mutations.

　　The finding comes weeks after leading scientists reported children born to men over the age of 45 run a higher risk of having autism and psychiatric disorders.

　　With age, sperm-producing cells do not copy a man's DNA as effectively, leading to genetic mutations.

　　Martin Fielder, an anthropologist at Vienna University, told the Sunday Times: 'Every 16 years the mutation rate doubles. Other researchers found 25 mutations per sperm in a 20-year-old, but at age 40 it is 65 mutations. By 56, it doubles again.

　　'The effect is very visible - someone born to a father of 22 is already 5-10 per cent more attractive than those with a 40-year-old father and the difference grows with the age gap.'

　　In contrast, women pass on a maximum of 15 mutations to their baby, regardless of age, according to the study published in the journal Nature.

　　Surveying a group of six men and six women, researchers showed them each 4,018 photographs of 18-20-year-old men and 4,416 of women the same age, and asked to rate their attractiveness.

　　Those with older fathers were consistently rated less attractive.

　　However, the offspring of older men, though less attractive, are likely to outlive their peers with younger fathers, it is claimed.

　　Professor Lee Smith, a geneticist at Edinburgh University, told the Sunday Times other research found such children have longer telomeres - the caps on the end of chromosomes - which are associated with longer life.

　　But the mounting research connecting parents' age with autism is cause for concern, experts warn.

　　Autism is an umbrella term for a range of developmental disorders that have a lifelong effect on someone’s ability to interact socially and communicate.

　　In the UK, around one in 100 adults is thought to be affected by autism, mostly men, caused by a combination of genetic and environmental factors.

　　Researchers said men should be advised about the potential problems in order to help their personal decision-making when it came to having fathering children at older ages.

　　They warned that advancing paternal age posed a risk of ‘numerous public health and societal problems’.

　　Among well-known older dads are Simon Cowell, 54, whose son was born earlier this month, and comedian Frank Skinner whose first child was born in 2012 when he was 55.

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