高齡為父不利于子女健康

Sir Mick Jagger embodies what one writer has called paleo-fatherhood, or the trend of becoming a dad in later life. He was 73 when Deveraux, his eighth child, was born to his 29-year-old partner, ballerina Melanie Hamrick.

米克•賈格爾爵士(Sir Mick Jagger)代表了一位作家所說的“大齡父親”趨勢。在他73歲時，他的29歲女友、芭蕾舞演員米蘭妮•哈姆里克(Melanie Hamrick)為他生下了他的第8個孩子德沃羅(Deveraux)。

The Rolling Stone is an extreme example but there has been a shift to older parenthood in recent decades. In 2015, first-time dads in the UK were 33 and first-time mothers were 30, on average four years older than was the case 40 years ago.

這位滾石樂隊(Rolling Stone)的搖滾巨星是一個極端的例子，但最近幾十年，晚生育的趨勢確實存在。2015年，英國男性首次當(dāng)父親的平均年齡是33歲，女性首次當(dāng)母親的平均年齡是30歲，比40年前的平均水平晚4年。

Discussion has tended to focus on women’s declining fertility, but paternal age seems to matter too.

人們的討論往往聚焦于女性生育率的不斷下降，但父親的生育年齡似乎也很重要。

There is fairly robust evidence that fathers who conceive in their forties or older have children who run two to three times the usual risk of developing an autism spectrum disorder and schizophrenia. Other studies have implicated advanced paternal age (usually defined as over 40, though different studies use different thresholds) in low academic achievement. This matters: in 2015, 15 per cent of new fathers in the UK were aged 40 or over.

有相當(dāng)有力的證據(jù)表明，在40多歲或以上生育孩子的父親，其子女患自閉癥譜系障礙和精神分裂癥的幾率是通常水平的兩到三倍。其他研究表明，父親生育年齡偏大(通常定義為超過40歲，不過不同研究使用的標(biāo)準(zhǔn)不同)會導(dǎo)致子女學(xué)校成績較低。這很重要：2015年，英國15%的新爸爸年齡在40歲以上。

A paper out this month suggests that the children of both atypically young and old fathers are more likely to show unusual patterns of social development, and to end up more socially challenged than their peers.

本月發(fā)表的一篇論文顯示，父親生育年齡過小或過大，其子女更有可能出現(xiàn)異常的社交發(fā)展模式，與同齡人相比，他們最終在社交方面遇到的挑戰(zhàn)更大。

The reasons for this are unclear but the findings highlight the emerging association between delayed fatherhood and higher health risks for offspring.

其中的原因尚不明確，但研究結(jié)果突顯出，男性晚生育與子女健康風(fēng)險更高之間是有相關(guān)性的。

The big question is whether this association stems from age-related genetic changes in sperm, or whether the men who become fathers later in life already have social difficulties that delay conception, and which then get passed on to the next generation.

關(guān)鍵問題是，這種相關(guān)性是來自精子中與年齡相關(guān)的基因變異，還是那些晚生育的男性本已存在社交障礙，由此耽擱了生育，而這種社交障礙又遺傳到了下一代身上。

The new research was led by Dr Magdalena Janecka, from the Seaver Autism Center for Research and Treatment, at the Mount Sinai Hospital in New York. It looked at data collected on 15,000 pairs of twins between the ages of four and 16, including social development, conduct with peers, and hyperactivity, and ruled out those already diagnosed with autism.

這項新研究的帶頭人是紐約西奈山醫(yī)學(xué)院(Mount Sinai Hospital)西維爾自閉癥研究和治療中心(Seaver Autism Center for Research and Treatment)的瑪格達(dá)萊娜•亞內(nèi)卡博士(Dr Magdalena Janecka)。研究分析了1.5萬對年齡在4歲至16歲的雙胞胎的數(shù)據(jù)，包括社交發(fā)展、與同齡人一起的表現(xiàn)、以及過度活躍表現(xiàn)，并排除了那些已被診斷為自閉癥的孩子。

It found that children born to fathers aged either under 25 or over 51 were more socially skilled than their peers in their early development. By adolescence, however, the same children had fallen behind socially.

研究發(fā)現(xiàn)，在早期發(fā)育中，那些出生時父親年齡在25歲以下或51歲以上的孩子的社交能力要高于同齡人。然而，到了青少年時期，這些孩子的社交能力則出現(xiàn)落后。

Their findings, published this month in the Journal of the American Academy of Child and Adolescent Psychiatry, were independent of the mother’s age.

這些研究結(jié)果發(fā)表在本月的《美國兒童和青少年精神病雜志》(Journal of the American Academy of Child and Adolescent Psychiatry)上。研究結(jié)果與母親年齡無關(guān)。

Dr Janecka concludes that “social skills are a key domain affected by paternal age . . . in extreme cases, these effects may contribute to clinical disorders”.

亞內(nèi)卡博士總結(jié)稱，“社交能力是受父親生育年齡影響的主要領(lǐng)域……在極端例子里，這些影響可能會引發(fā)臨床疾病”。

The researchers theorise that paternal age influences how a child’s brain matures, with further study possibly shedding light on how autism and schizophrenia develop.

研究人員提出如下理論：父親生育年齡會影響兒童大腦發(fā)育。進(jìn)一步的研究可能會揭示自閉癥和精神分裂癥是如何發(fā)展的。

Scientists suggest that random genetic mutations during sperm production might explain the association. The precursors to sperm cells are continually dividing, with each division representing the opportunity for a genetic typo, or copying mistake.

科學(xué)家表示，在精子形成期間的隨機(jī)基因突變或許可以解釋這種相關(guān)性。精細(xì)胞的前體不斷分裂，每次分裂都有可能出現(xiàn)基因錯排或者復(fù)制錯誤。

The rate of these so-called de novo mutations has been estimated to double roughly every 16 years, meaning older men shoulder many more mutations than younger men.

據(jù)估計，所謂的新生突變率大約每16年增加一倍，這意味著年齡較大男性攜帶的突變基因要遠(yuǎn)遠(yuǎn)多于較年輕男性。

Others have suggested that the rate of such mutations is simply not high enough to account fully for the higher risk of psychiatric illness in the children of older fathers.

還有人提出，這種基因突變率還不夠高，不足以完整解釋為何大齡父親的子女患精神疾病的風(fēng)險更高。

A 2016 paper in Nature by scientists from the Queensland Brain Institute concluded that “genetic risk factors shared by older fathers and their offspring are a credible alternative explanation” to the mutated sperm theory.

《自然》雜志(Nature) 2016年一篇來自昆士蘭腦神經(jīng)科學(xué)研究所(Queensland Brain Institute)科學(xué)家的論文總結(jié)稱，精子基因變異理論的“另一種可信解釋是大齡父親及其子女共有一些基因風(fēng)險因素”。

In other words, men who are at greater risk of psychiatric illness tend to become fathers later in life — and their kids simply inherit that greater risk.

換句話說，患精神疾病風(fēng)險較高的男性往往會推遲生育年齡，而他們的子女又會遺傳這種較高的風(fēng)險。

If this is the case, the biological clock does not tick as urgently for men as for women. But the science is by no means settled, partly because there are so many other factors aside from parental age — such as childhood neglect and drug use — that influence mental health.

要是這樣的話，那么男性生物鐘的轉(zhuǎn)動并不像女性那樣快。但科學(xué)并非一錘定音，部分原因是除了父母年齡，影響心理健康的還有很多其他因素，例如童年時期被忽視以及吸毒。

One major study, which supports the link between paternal age, psychiatric risk and academic outcome, involved combing the data of 2.6m Swedes. It was able to compare siblings born to the same father. If the siblings were simply inheriting risk, paternal age would be immaterial. In fact, as paternal age rises, so does the risk of psychiatric illness and lower school grades.

另一項重大研究分析了260萬瑞典人的數(shù)據(jù)，研究結(jié)果證明，父親生育年齡、精神疾病風(fēng)險和學(xué)習(xí)成績之間是存在關(guān)系的。該研究得以將同一位父親的多位子女進(jìn)行對比。如果子女都遺傳了風(fēng)險，那么父親的生育年齡就不重要了。實際上，隨著父親生育年齡的提高，子女患上精神疾病和學(xué)習(xí)成績較低的風(fēng)險就越高。

“It would make sense that the effect lies in the integrity of the sperm line,” says Professor Frances Happé, an autism expert at the Institute of Psychiatry, King’s College London, and a co-author of the JAACAP paper.

倫敦國王學(xué)院(King’s College London)精神病學(xué)研究所(Institute of Psychiatry)自閉癥專家弗朗西斯•哈佩(Frances Happé)教授表示：“問題有可能就出在完整的精子生產(chǎn)鏈上。”她是上述《美國兒童和青少年精神病雜志》那篇論文的聯(lián)合作者。

Men, she adds, make sperm throughout life. The production process may be vulnerable to environmental effects as well as random mutations.

她補(bǔ)充稱，男性終身都在制造精子。制造過程很容易受到環(huán)境以及隨機(jī)基因突變的影響。

Professor Adam Balen, chair of the British Fertility Society, says the study “doesn’t give a definitive answer about the biological or social causes of autism in the children of older men”.

英國生育學(xué)會(British Fertility Society)主席亞當(dāng)•巴倫(Adam Balen)教授表示，這項研究“沒有就大齡父親的子女患自閉癥的生物學(xué)或社會學(xué)原因給出定論。”

He adds: “As people in more developed economies are choosing to have children later in life, we need to understand what that might mean for the overall health and wellbeing of future generations.”

他補(bǔ)充稱：“經(jīng)濟(jì)越發(fā)達(dá)地區(qū)的人們生育年齡越晚，我們需要弄明白，這對于未來幾代人的整體健康和幸?？赡芤馕吨裁?。”

Prof Happé also warns that, since it is impossible to predict which men are affected, couples should not plan families around this research.

哈佩教授還警告稱，現(xiàn)在還無法預(yù)測哪類男性會受到影響，因此夫婦不應(yīng)根據(jù)這項研究來制定生育計劃。

In the meantime, silver-haired dads are on the rise, thanks to a collision of social trends. Many men and women want to taste career success — and the financial stability that accompanies it — before procreating. Relatively high divorce rates are producing second broods, and reproductive science is extending the age limits to parenting that were previously set by nature. Celebrity fathers are removing the stigma of late parenthood: Sir Paul McCartney and Clint Eastwood became sixtysomething dads.

與此同時，由于社會趨勢的碰撞，銀發(fā)爸爸們正在增多。很多男女希望先品嘗事業(yè)的成功以及伴隨而來的經(jīng)濟(jì)穩(wěn)定再生育。相對較高的離婚率帶來了再婚再育，而生殖科學(xué)的發(fā)展也在不斷提高以往由自然設(shè)定的生育年齡限制。名人父親也正消除老來得子的恥辱感：保羅•麥卡特尼爵士(Sir Paul McCartney)和克林特•伊斯特伍德(Clint Eastwood)都是在60多歲當(dāng)爸爸的。

There might even be advantages amid the (hypothetical) genetic gloom: work might not compete as much; finances might be less strained.

(假想的)基因低潮時期甚至可能還有好處：工作可能沒有那么多競爭;經(jīng)濟(jì)狀況可能沒那么緊張。

Perhaps Sir Mick had thought it through, after all.

畢竟，米克爵士或許已經(jīng)仔細(xì)考慮過了。