2016年美国大选可能改变了加拿大的出生性别比

2016年美国大选可能改变了加拿大的出生性别比

The 2016 election had some unexpected effects in surprising places. Rising to the top of that list is the possibility of a reduced number of boys born in parts of Canada.

2016年大选在一些出人意料的地方产生了一些意想不到的影响。排在首位的是在加拿大部分地区出生的男孩数量减少的可能性。

Disastrous events such as wars or famines can alter the proportion of male and female babies born in the years thereafter. The shift is small but can easily be detected when millions of births are involved, such as during both world wars. Even events that do not affect mothers directly can have an impact – fewer boys than normal were born in the USA shortly after 9/11, or in Norway after the 2011 far right massacre.

灾难性的事件，如战争或饥荒，会改变此后几年出生的男婴和女婴的比例。这种变化很小，但当涉及到数百万人的出生时，比如在两次世界大战期间，就很容易发现。即使是不直接影响母亲的事件也会产生影响——9/11事件后不久，美国出生的男孩数量低于正常水平，或者2011年极右翼大屠杀后，挪威出生的男孩数量低于正常水平。

Stephen Luntz

Dr Ravi Retnakaran and Dr Chang Ye of Mount Sinai Hospital, Toronto, wondered if election results could do the same thing. Naturally, this would be harder to detect – a whole nation is traumatized by terrorism, but elections make about as many people happy as sad.

多伦多西奈山医院的Ravi Retnakaran博士和Chang Ye博士想知道选举结果是否也能起到同样的作用。当然，这很难察觉——整个国家都受到了恐怖主义的创伤，但选举让同样多的人感到高兴，也让同样多的人感到悲伤。

On the other hand, other countries are sometimes fairly united in who they want to win their neighbors' elections. American elections transfix the world, and polling companies sometimes ask the voters of other nations who they would vote for if they could. Canadians consistently indicate an overwhelming preference for Democrats over Republicans, including at the 2016 presidential election. Consequently, Retnakaran and Ye looked at the numbers of boys and girls born in Ontario before and after the election.

另一方面，其他国家有时在他们希望谁赢得邻国选举的问题上是相当团结的。美国的选举震惊了世界，投票公司有时会问其他国家的选民，如果他们可以的话，他们会把票投给谁。包括在2016年的总统大选中，加拿大人始终表明，他们对民主党人的偏爱超过了共和党人。因此，Retnakaran和Ye研究了在选举前后安大略省出生的男孩和女孩的数量。

In BMJ Open, they report a sharp dip in the proportion of boys born in March 2017, which slowly returned to normal in the following months.

在BMJ公开赛上，他们报告说2017年3月出生的男孩比例急剧下降，在接下来的几个月里慢慢恢复正常。

Effects usually show up 3-5 months after tragedies, but because there could have been many other explanations, the authors drilled down further into the data. Left-leaning parts of Ontario saw an even larger shift than the provincial average. More conservative areas had no change at all. Even many conservative Canadians preferred Hillary Clinton to Donald Trump, but it is to be expected they were less distressed by the result than their counterparts who support the (Canadian) Liberals, NDP, or Greens.

这些影响通常在悲剧发生3-5个月后才显现出来，但因为可能有许多其他的解释，作者进一步深入研究了数据。安大略左倾地区的变化甚至比该省的平均值还要大。较为保守的地区则完全没有变化。甚至许多保守的加拿大人也更喜欢希拉里·克林顿，而不是唐纳德·特朗普，但可以预见的是，与支持(加拿大)自由党、新民主党或绿党的加拿大人相比，他们对选举结果不那么沮丧。

Although the full reason bad news affects birth ratios remains debated, male fetuses are known to be more susceptible to maternal stress than female ones. Considerably more boys than girls are conceived, but a higher rate of miscarriages brings the ratio closer to balance at birth. Anything that causes a spike in pre-term deaths will therefore show up in the sex ratios, given a sufficiently large sample. The effect can even be seen in seasonal data, with hot summers or cold winters having a small but noticeable impact.

尽管坏消息影响出生率的完整原因仍有争议，但众所周知，男性胎儿比女性胎儿更容易受到母亲压力的影响。怀上的男孩比女孩多得多，但较高的流产率使这一比例在出生时更接近平衡。因此，只要有足够大的样本，任何导致早产死亡激增的因素都将出现在性别比例中。这种影响甚至可以在季节数据中看到，炎热的夏季或寒冷的冬季产生的影响虽小，但很明显。

The authors acknowledge that without knowing the politics of individual expectant mothers, they can't be certain the election, rather than some other event around the same time, caused the effect they measured, but the timing and distribution are striking.

作者承认，如果不了解准妈妈们各自的政治倾向，他们就无法确定是选举，而不是与此同时发生的其他事件，导致了他们所测量的影响，但时间和分布是惊人的。