英语网刊订阅
请填写e-mail地址
然后按相应的按钮:
在线投稿
   
   
 
 
  英文听力:经典教程
  英语科普:男孩性成
  英语笑话:Doctor's
  英语美文:Self-Dis
  英语新闻:联想第二
  英语电影对白:Di
  雅思口语话题:读书
  英语口语对话:询问
  情景英语会话:买纪
  英语课程:朗文国际
 
 
英语网刊第254期
英语网刊第253期
英语网刊第252期
英语网刊第251期
英语网刊第250期
英语网刊第249期
英语网刊第248期
英语网刊第247期
英语网刊第246期
英语网刊第245期
英语网刊第235期
 
当前位置:首页>英语网刊>2011年英语网刊>英语网刊第235期> 英语科普:男孩性成熟的年龄越来越小
英语科普:男孩性成熟的年龄越来越小
在线英语听力室 (2011-08-20)  字体: [ ]  

Boys are maturing physically earlier than ever before. The age of sexual maturity has been decreasing by about 2.5 months each decade at least since the middle of the 18th century. Joshua Goldstein, director of the Max Planck Institute for Demographic Research in Rostock (MPIDR), has used mortality data to demonstrate this trend, which until now was difficult to decipher(解释) . What had already been established for girls now seems to also be true for boys: the time period during which young people are sexually mature but socially not yet considered adults is expanding. "The reason for earlier maturity for boys, as with girls, is probably because nutrition and disease environments are getting more favourable for it," says demographer(人口学家) Joshua Goldstein. It has long been documented by medical records that girls are experiencing their first menstruation(月经) earlier and earlier. But comparable data analysis for boys did not exist. Goldstein resolved this gap by studying demographic data related to mortality. When male hormone production during puberty reaches a maximum level the probability of dying jumps up. This phenomenon, called the "accident hump," exists in almost all societies and is statistically well documented.

Goldstein discovered that the maximum mortality value of the accident hump shifted to earlier age by 2.5 months for each decade since the mid-1700s, or just over two years per century. Accordingly, the age of boys' sexual maturity decreased at the same rate. Essentially, the data showed that the age of sexual maturity is getting younger and younger since the accident hump is occurring earlier and earlier. (Research included data for Sweden, Denmark, Norway, Great Britain and Italy. Since 1950 the data is no longer clear but indicates stagnation停滞.) The maximum of the accident hump occurs in the late phase of puberty, after males reach reproductive capability and their voice changes.

英语科普


[收藏] [推荐] [返回顶部] [打印本页] [关闭窗口]