Older dads' children are 'less intelligent'
Children fathered by older men are likely to be less intelligent than the offspring of younger dads, Australian and US scientists have found in a report published yesterday.
The surprise result contrasted sharply with earlier studies showing that older mothers produced children more likely to record above average intelligence scores, the researchers concluded.
Lead scientist John McGrath, from the Queensland Brain Institute, said the result was a world first and had implications for men in Western societies who have delayed fatherhood until their 40s or older.
"The results were quite startling as it was thought that the age of the father was less of a concern compared to the age of the mother," McGrath said. "Now we are getting more evidence of the age of the father being just as important - the older a dad is, the worse his children tend to do in intelligence tests."
Researchers examined data collected on 33,000 children in the US between 1959 and 1965 fathered by men aged from 15 to 65. They found that the children of older dads performed less well in intelligence tests conducted at age eight months, four years and seven years.
The researchers said previous studies had linked older fathers to an increased risk of health problems in their children, including schizophrenia, autism, dyslexia, epilepsy and dwarfism.
However, the study published in the journal Public Library of Science Medicine is the first to suggest there is also a link with general intelligence.
The trend towards children of older fathers being less intelligent remained statistically significant even when factors such as socio-economic status and parental mental health were taken into account.
McGrath said the research team could not draw conclusions on how having an older father impacted on children later in life because the subjects in their study were only examined until they were aged seven.
"It is feasible that the offspring of older fathers 'catch up' during later childhood," the researcher said.
"How the subtle neurocognitive features associated with (older fathers) translate into later educational and mental health outcomes across the lifespan remains to be determined."
爸爸年齡大 孩子不聰明？
美國和澳大利亞的科學家在昨日公布的一份報告中稱，年齡較大的男性所生的孩子可能不如年輕男性的孩子聰明。
這一令人驚訝的結果與之前的研究發(fā)現(xiàn)形成鮮明對比。之前的研究表明，大齡媽媽所生的孩子智商得分超過平均水平的可能性較大。
昆士蘭腦研究所首席科學家約翰?麥克格雷斯稱，該研究成果在世界范圍內(nèi)尚屬首例，同時對西方國家那些等到40多歲甚至更晚才要孩子的男性具有警示作用。
麥克格雷斯說：“研究結果十分令人吃驚。之前的觀點認為，與母親的年齡相比，父親的年齡沒那么重要。現(xiàn)在有越來越多的證據(jù)表明父親的年齡也很重要，父親年齡越大，孩子智商測驗的得分越低。“”
研究人員對1959年至1965年間出生的3.3萬名美國兒童的相關數(shù)據(jù)進行了分析，這些孩子出生時父親的年齡在15至65歲之間。研究人員發(fā)現(xiàn)，從孩子在8個月、4歲和7歲時接受的智商測驗結果看，年齡較大的父親的孩子智商得分較低。
研究人員稱，之前的研究表明，父親年齡偏大會增加孩子患精神分裂癥、孤獨癥、誦讀困難、癲癇癥和侏儒癥等疾病的風險。
而這項發(fā)表于《公共科學圖書館：醫(yī)學》期刊上的研究首次表明，父親的年齡與孩子的一般智力也有關。
即使將社會經(jīng)濟地位和父母精神健康等因素考慮在內(nèi)，年齡較大的爸爸易生笨小孩這一趨勢從統(tǒng)計角度看也很明顯。
麥克格雷斯稱，由于該研究在調查對象7歲時就終止了，所以研究小組無法判斷父親年齡偏大會對孩子7歲之后的智力發(fā)展造成怎樣的影響。
一位研究人員說：“年齡偏大的爸爸所生的孩子的智力在幼年晚期或許會趕上其他孩子，這也是有可能的。“”
“目前還不清楚與父親年齡有關的微妙的神經(jīng)認知特征對孩子日后的教育和心理健康會造成怎樣的影響。“”
