来源：《科学美国人》2022年3月号
For decades women have heard distressing warnings about their “biological clocks.” We have been repeatedly told that fertility drops dramatically after age 30, so people who want children either need to get moving or else freeze their eggs. Embryo freezing is now a big business, and discussions of it are commonplace among young professional women.
几十年来，女性一直听到有关她们“生物钟”的令人不安的警告。我们一再被告知，30岁以后生育率会急剧下降，所以想要孩子的人要么赶紧行动起来，要么把卵子冷冻起来。胚胎冷冻现在是一桩大生意，年轻的职业女性对此的讨论很普遍。
But the claim is based on very sparse data, much of them of dubious quality or relevance. The notion stems largely from a 2004 paper based on records from 1670 through 1830. Many things have changed since then, including medical care and nutrition. In wealthier nations, people are now healthier overall and likely to be more fertile for longer periods of their lives. Systematic data collected by the National Center for Health Statistics demonstrate that from 1980 to 2002 fertility rates for women aged 30 and older were going up. It is also worth noting that when infertility treatments started to become more common and more clinics began opening in the 1980s and 1990s, alarms over biological clocks were being sounded by this growing industry with a self-interest in the matter.
但这一说法是基于非常稀少的数据，其中许多数据的质量或相关性令人怀疑。女性生育能力在30岁后下降这个观念主要来源于2004年的一篇论文，该论文基于1670年至1830年的数据记录。但那个年代之后，许多事情都发生了变化，包括医疗保健和营养。在较富裕的国家，人们现在总体上更健康，并且可能在更长的生命周期内更具生育能力。美国卫生统计中心收集的系统数据表明，从1980年到2002年，30岁及以上妇女的生育率在上升。同样值得注意的是，在20世纪80年代和90年代，随着不孕症治疗变得越来越普遍，越来越多的诊所开始开业，这个不断发展的行业出于自身利益，正在敲响生物钟的报警器。
Despite the importance of childbearing to so many people—and although infertility treatments are costly, have only modest success rates and are not risk-free—the sad fact is that robust studies of age-dependent infertility are scant. The data we do have tend to show that although fertility does decline slightly at older ages, most women continue to be fertile well into their 30s, and for many people that is a good time to have children. There's a long-standing cultural tendency to blame infertility on women, but when a couple is infertile it is equally likely that the cause can be traced to the man. Male fertility also declines with age, but how often do you hear warnings about the male biological clock?
尽管生育对很多人来说很重要，尽管不孕症治疗费用昂贵，成功率不高，而且也并非毫无风险，但令人遗憾的是，对年龄依赖性不孕症的可靠研究却很少。我们掌握的数据往往表明，尽管年龄越大，生育能力会有轻微下降，但大多数女性在30多岁时仍能保持生育能力，对许多人来说，这仍是生孩子的好时机。长期以来，文化倾向将不孕归咎于女性，但当一对夫妇不能生育时，同样可能的原因可以追溯到男性。男性生育能力也会随着年龄的增长而下降，但你是否经常听到有关男性生物钟的警告呢？
Like the female clock, many health beliefs have shallow and feeble roots. But sometimes the wisdom of the crowd is supported by facts: most of us do need around eight hours of sleep a night, for instance. So where does this leave someone trying to make sense of what they hear or read?
就像女性的生物钟一样，许多健康观念的根基都很浅，也很薄弱。但有时，大众的智慧是有事实支持的：例如，我们大多数人每晚确实需要大约8小时的睡眠。那么，这对于试图理解他们听到或读到的内容的人来说意味着什么呢？
Well, for one thing, people should be skeptical of any large claim based on one study. Good science requires building a multifaceted and detailed case, which takes time and is almost never achieved in a single piece of research. The online medical library PubMed.gov enables people to find out if a subject is well studied or not. And the National Institutes of Health has a medical consensus program that has published more than 160 statements on various diseases and their treatments. Some of them are actually readable, and none relies solely on data from more than a century ago.
首先，人们应该对任何仅仅基于一项研究的重大主张持怀疑态度。好的科学需要建立在多层面和详细的论证之上，这需要时间，而且几乎不可能在一项研究中实现。在线医学图书馆PubMed.gov使人们能够了解某一学科是否被充分研究。美国国立卫生研究院有一个医学共识项目，已经发表了160多篇关于各种疾病及其治疗的报告。其中一些通俗易懂，但没有哪篇会仅仅依赖于一组一个多世纪以前的数据。