They dote on their grandchildren, offer a treasure trove of wisdom and provide an invaluable babysitting service.
But it seems grandparents have a more crucial role - survival of the species.
Their practical and financial support helps keep youngsters fit and healthy, while their love and ability to listen helps children and teens get through difficult periods such as the divorce of their parents.
The conclusions come from Swiss and Australian researchers who analysed previous studies from around the world to pin down the role of grandparents. Several studies have linked grandmothers, in particular, with survival of the species.
A maternal grandmother, a child's mother's mother, is particularly nurturing. This could be because they can be more certain than any other grandparent that the child is part of their genetic line, with DNA that has not been tainted by affairs, and so worth the investment.
Maternal grandfathers produce the second highest level of care, followed by paternal grandmothers. Paternal grandfathers generally show the least interest, the journal Psychological Science reports.
University of Western Australia researcher David Coall said grandparents may also be motivated by the thought of having someone to take care of them when they grow old. If this is the case, they will shower their attention on the grandchildren whose parents are most likely to reciprocate in the future. Children don't just benefit from better physical health if a grandparent is around - the emotional support can also be of huge value.


据英国《每日邮报》11月22日报道，祖父母宠爱自己的孙辈，为他们提供了一个珍贵的智慧宝库以及无价的看护服务。
但似乎祖父母还有一个更加重要的作用--保护物种的生存。
他们在实际生活和经济上的支持帮助青少年保持身体健康，而他们的爱护和倾听的能力则能够帮助儿童和青少年度过困难的时期，比如说父母离异。

这一结论出自于瑞士和澳大利亚的研究人员，他们分析了此前世界各地的相关研究，以确定祖父母的作用。其中一些研究特别指出了祖母与物种生存的关系。

外祖母，也就是孩子的母亲的母亲，在养育孙辈上尤其用心。这可能是因为比起其他祖父母辈，她们更加确信孩子的DNA没有被其它什么风流韵事干扰，的确是她们基因延续的一部分，所以值得她们付出爱。


据《心理科学》杂志报道，外祖父在付出关心的多少上排行第二，紧接着是祖母，而祖父则对宠爱孙辈表现出了相对最少的兴趣。

澳大利亚西澳大学的研究员大卫·克奥尔说，祖父母会这样做的思想动机，可能是因为他们希望在老了以后能够有人照顾他们。如果是这样的话，他们就会对孙子辈倾注所有的注意力，因为孙辈的父母是最有可能在未来回报他们的人。如果有祖父母在身边，不仅有益于孩子的身体健康--情感上的支持也非常有价值。

• wisdom [´wizdəm] n.智慧，聪明，才智 (初中英语单词)
• financial [fi´nænʃəl] a.金融的，财政的 (初中英语单词)
• healthy [´helθi] a.健康的 (初中英语单词)
• ability [ə´biliti] n.(办事)能力；才干 (初中英语单词)
• divorce [di´vɔ:s] n.离婚 vt.同....离婚 (初中英语单词)
• previous [´pri:viəs] a.先，前，以前的 (初中英语单词)
• grandmother [´græn,mʌðə] n.(外)祖母 (初中英语单词)
• journal [´dʒə:nəl] n.日记；日报；杂志 (初中英语单词)
• western [´westən] a.西的；西方的 (初中英语单词)
• shower [´ʃauə] n.展出者；阵雨；淋浴 (初中英语单词)
• physical [´fizikəl] a.物质的；有形的 (初中英语单词)
• emotional [i´məuʃənəl] a.易动感情的；情感的 (初中英语单词)
• maternal [mə´tə:nl] a.母亲的；母性(系)的 (英语四级单词)
• psychological [,saikə´lɔdʒikəl] a.心理学(上)的 (英语四级单词)
• invaluable [in´væljuəbəl] a.无价的，非常重要的 (英语六级单词)
• paternal [pə´tə:nl] a.(象)父亲的；父方的 (英语六级单词)