Most males in the animal kingdom do little parenting. Sometimes, though, parental investment by a male pays off. Songbird chicks

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问题     Most males in the animal kingdom do little parenting. Sometimes, though, parental investment by a male pays off. Songbird chicks are usually tended by both mother and father. Wolf packs see alpha males and females collaborate to raise the cubs. And in human beings, too, the children’s father hangs around to lend a hand in bringing up the kids. Sometimes.
    Understanding why some men settle down to form families with the mothers of their children, and others don’t, is normally seen as the prerogative of social science. But biology has a role, too. And the latest work by Lee Gettler of the University of Notre Dame, in Indiana, clarifies how part of that biological mechanism operates.
    Previous studies suggest that high levels of testosterone, the principal male hormone, are bad for family life. Fathers with lower testosterone levels provide more child care and are better partners to the children’s mothers. Conversely, high-testosterone males are less likely to stick around.
    Dr Gettler has shown something further. This is that a man’s adult testosterone level seems correlated with whether his father was present during his teenage years. His data come from a survey begun in Cebu City, in the Philippines, in 1983. This monitored the health and nutrition of 966 men enrolled as babies. It also collected extensive information on whether the fathers of these men were around and providing parental care in the households in which they were brought up. It further documented whether participants got married, had children and, if they did, whether they participated in child care. Crucially, it also measured their testosterone levels at the ages of 21, 26 and 30.
    Overall, Dr Gettler and his colleagues found that on becoming fathers, men had lower testosterone levels if their own fathers had lived with them and been involved in their care during their teenage years. Specifically, if that had happened, testosterone levels in their saliva were 16% below those of men whose fathers had not stuck around to help raise them.
    This difference has two possible explanations. One is that it is directly genetic, with high-testosterone fathers (those least likely to stick around) begetting high-testosterone sons. In this case the correlation with paternal absence would be a coincidence. The other is that teenage experience actually modulates testosterone levels. This explanation, which Dr Gettler favours, could lead to a vicious circle of high-testosterone men abandoning their sons, who thus become high-testosterone in their turn.
    Testosterone levels are not completely deterministic in the matter of parental care. Some of those in the survey whose fathers were absent during their adolescence, and who ended up with high levels of the hormone, did nevertheless became nurturing parents.
Gettler believes that a man’s high level of testosterone may________.

选项 A、produce a father-absent environment for his descendants
B、be directly transmitted to his sons through genes
C、prevent him from becoming a good partner of his wife
D、have no relationship with his teenage experience

答案A

解析 细节题。根据题干中的Gettler、high level of testosterone可定位至第六段。最后一句提到,could lead to a vicious circle of high-testosterone men abandoning their sons, who thus become high-testosterone in their turn (这可能会形成一个恶性循环:睾酮水平高的男性抛弃自己的儿子,而他们的儿子也因此成了睾酮水平高的人),A项符合文意,故正确。B项属于是非混淆,格特勒不同意这个观点,故排除。C项属于偷换概念,由第三段第二句推断出,睾酮水平高会阻止他成为一个辅助孩子母亲的好父亲,而不是阻止他成为妻子的好伴侣,故排除。D项属于是非混淆,格特勒博士赞成第二种解释,因此他相信睾酮水平与青春期经历有关,故排除该选项。故本题答案为A。
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