“女生们的大姨妈会一起来”这事，引起了科学家的高度关注！

It's commonly believed that women who live together eventually experience the syncing of their monthly periods. But couldit just be chance?

有一种普遍的说法是女人们在一起住久了，渐渐的她们的大姨妈都会变得同步起来。但这仅仅是巧合吗？

The theory behind the syncing of menstrual cycles is that women's pheromones interact when they are in close proximity, causing them to have their period at the same time. Many females buy into it.

“大姨妈同步”的（科学）理论就是，当女人近距离相处的时候，身体里的信息素会互相影响，这就是造成大姨妈同步的原因。许多女人都信这个。

"I definitely think it's true," says Emma. "It would be too much of a coincidence otherwise."

“这肯定是事实，”爱玛说，“要不然，这真的也太巧了吧？”

Emma, 24, lived with five girls atuniversity. She says that within a few months they all had their period at the same time.

爱玛是个24岁的大学生，现在和5个女孩子一起住。她说，没几个月，她们所有人的大姨妈都同步了。

"It's a popular belief," says Alexandra Alvergne, associate professor in biocultural anthropology at the University of Oxford.

“这个观点很普遍”，牛津大学人类学生物文化学的副教授，亚历山德拉说。

"As humans we always like exciting stories. We want to explain what we observe by something that is meaningful."

“人类喜欢激动人心的故事。我们想要通过自己的观察，解释一些有意义的事情。”

Alvergne has tried to review the evidence for this phenomenon. She says the idea started with research findings published in Nature, a scientific journal, in 1971. A researcher called Martha McClintock studied the menstrual cycles of 135 women in an American college.

阿尔维格尼尝试重新审阅这种现象的证据。她说这个想法来自1971年出版的《自然》科学杂志上的一个研究。一位名为玛莎. 麦克林托克的研究员对一所美国大学的135名女性的月经周期进行了研究。

"[McClintock] found that the onset of the date of menstruation was more similar among friends and roommates than among random pairings of women," says Alvergne.

“麦克林托克发现，在朋友和室友之间，月经开始时间的相似程度，比随机配对的女性，要高很多。”阿尔维格尼说。

Dr McClintock hypothesised that this was because the women who were spending time together had the chance for their pheromones to affect each other.

麦克林托克博士猜测，那是因为相处时间比较久的女生，为互相影响的信息素提供了机会。

And why would this happen?

为什么会发生这样的事儿？

The most prevalent theory was that it was an evolved strategy among females toco - operate with each other - to stop becoming a kind of harem for a single dominant man.

最流行的观点是女人们之间互相合作的进化战略-为了阻止一个男人妻妾成群，操控女人。

The idea is that if women had synchronised cycles, they would all be fertile at the same time - so one man would not beable to reproduce with them all.

如果女人们大姨妈都同步了，她们就可以同时备孕。而一个男人不可能同时跟这么多女人生孩子。

Other studies, some in humans and some in other primates, seemed to show similar results.

其它的一些研究，其中一些是跟人类相关的，一些是其它的灵长类动物，看起来都有相似的结果。

But, there were also studies that didn't find evidence of periods syncing. And people started to pick holes in the earlier research - critics identified problems in the people chosen for the study. The definition of when they were syncing was quite loose.

但是，也有一些研究发现没有女人大姨妈同步的证据。所以反对者们开始去挑之前研究的刺儿了。反对者认为问题出在被选中做研究的女人身上。之前的研究者对大姨妈同步的定义过于宽松。

Perhaps most importantly, critics pointed to the fact that in McClintock's 1971 findings she didn't explain why women's cycles were in sync.

更最重要的是，反对者指出，在1971年的研究里，麦克林托克博士并没有解释是什么原因造成的女人经期的同步。

This seems to go against what many women feel they experience.

这似乎是跟很多女人的亲身体验是截然相反的。

"If I spend any period of time with a woman who is menstruating, I will start my period," says Inez, 26. "My womb is a huge team player. It just wants to be one of the girls."

“如果我跟一个刚来大姨妈的女生相处了一段时间，我的大姨妈也来了。”26岁的伊内兹说，“我的子宫有强大的团队精神。它也想像其它的女孩子一样”

Not only that but Inez thinks some women have wombs that prefer to play a leadership role.

不仅如此，伊内兹认为一些女人的子宫喜欢扮演领导者的角色。

"I've got a classic beta womb. My friend Suzanne has an alpha womb. She will bring anyone on within a 10-mileradius. She walks in menstruating, everyone is reaching for the tampons."

“我的子宫是经典的测试版。我朋友苏珊娜的子宫就是加强版。她可以使10公里以内的所有女生都受到她影响。在她大姨妈刚来的时候，如果她到处走动，那每个女人都要去买卫生棉条了。”

（英大：好强大，好可怕！）

Some academics recently decided to find out if the findings of synchronicity of periods could be put down to chance. They looked at six years' worth of data of the menstrual cycles of our closecousins, baboons.

最近，一些研究机构决定找出“女性经期时间趋同”（的线索），看看能否有所发现。他们查阅了六年来人类的近亲狒狒的有价值的月经周期的数据。

"They proposed two models," says Alvergne. "One was the model with the exciting hypothesis" also knownas the "evolved strategy" in which women sync as a defence against dominant males." And the other model was the boring model. Where the patterns are explained by chance."

“他们重新提出了2种模式”，阿尔维格尼说。“一种是另人兴奋的假设，也就是被熟知的“女人进化战略”是女人用经期同步来对抗男人的主导地位。另外一种模式是让人感觉无聊的模式。这种模式是用意外来解释的。”

The researchers compared how much each model would account for the data being observed. They found that the model assuming that patterns would appear by chance was the best model by far.

研究人员对比了经过观察的每种模式有可能对数据造成的影响。他们发现假设这种现象偶然出现是迄今为止最好的模型。

More research could be carried out in the future that does reveal evidence that women's periods sync. But currently many researchers are sceptical.

未来会有更多的研究继续进行，并揭露女人大姨妈同步的证据。但现在许多研究者持怀疑态度。

所以，你觉得是意外？还是有科学依据的？

翻译：Becky

编辑：芒果