经济学人下载:双胞胎母亲更幸福

Alas, pinning down evolved relationships between fertility and health is tricky. Modern medicine and the pampering effects of economic growth mean that, these days, women everywhere give birth to fewer children than they did in the distant evolutionary past, when human bodies and physiology were forged—even as more of the offspring they do bear survive into adulthood. In Europe and North America this demographic transition began in earnest around 1870.

唉，控制生育和保持健康之间的关系是很难的。现代医学和经济的发展精心呵护的结果是，当人体和生理机能被伪造，这个时候的女性无论在哪里都会比处在以前缓慢发展时期的女性生的孩子要少，因为她们生的孩子大部分能活到成年。在欧洲和北美这个人口过渡开始于1870年左右。

One way round this is to look at records gathered before the demographic transition began. The problem is that few authorities then kept tabs diligently enough to provide adequate fodder for statistical analysis. One exception was Utah, a state largely settled in its early days by Mormons, who have always taken such matters seriously. As a result, Utah’s Pedigree and Population Resource, a database of which Dr Smith is the director, contains 1.6m genealogical records for people in the state from the early 1800s to the 1970s.

围绕着寻找记录及合并的方法要在人口过渡开始前完成。这个问题是只有很少的当局会勤奋的为统计分析提供足够的材料保持制表符。一个例外是犹他州，在早期有摩门教徒定居在此，他们总是严肃的对待事情。结果，在史密斯博士作为主管的一个数据库中，犹他州的血统和人口资源包括160万份在早期的1800世纪到1970世纪中居住于此的居民的家谱记录。

To test their theory that the bearers of twins are supermums, Dr Robson and Dr Smith scoured the records for women born between 1807 and 1899 who survived past the age of 50, when the menopause typically strikes. They excluded those married more than once, those widowed before they were 50 and also (this being Utah) those wives who were part of one of the polygamous marriages once legal among the state’s Mormon settlers. (In a study published earlier this year, Dr Smith and his colleagues found that the more wives a Mormon woman had to compete with for her husband’s attentions, the fewer children she was likely to produce.) This left them with some 59,000 women, around 4,600 of whom had given birth to twins at least once.

为了检验他们关于双胞胎母亲是超级妈妈的说法罗伯森博士和史密斯博士搜集了关于超过50岁的更年期正常来临并在1807年到1899年进行生产的妇女的资料。她们只结过一次婚，在50岁以前就守寡并且这些妻子是一夫多妻制婚姻的一部分，而这在这一地区的摩门教徒中是合法的。（今年早期发布的一项研究表明，史密斯博士和他的同事发现在众多妻子中，一个摩门妇女不得不为了吸引丈夫的关注而竞争，这样她很可能会生更少的孩子。）这样的妇女大约有59000名，其中4600名至少一次的生产双胞胎。