国外媒体:研究:未来女性将更适合晚育

Women will evolve into having children at older age

The fashion for having children later in life could lead to women becoming more fertile in their 40s and beyond, scientists have suggested.

As many women wait until they are older to give birth, only those with longer lasting¹ fertility genes² will be successful.

That means the average length of fertility will grow as their genes will be passed on to their children.

The study from the University of Sheffield shows that previously³ women would marry early and if widowed were too old to remarry thus favouring early childbirth in women.

But today's reluctance⁵ to settle down and reproduce until later in life could lead to fertility beginning to favour older women.

The researchers studied marriage patterns to trace the survival and marriage histories of 1,591 women.

Using 18th and 19th century Finnish records – a time when almost everyone got married and divorce was strictly⁶ forbidden.

They found that women aged⁷ 30 to 35 were the most likely to be married. Those that wed⁴ wealthy husbands were married at a younger age but to relatively⁸ older men, meaning family sizes were bigger but with an increased risk of widowhood.

The researchers say that this high chance of widowhood, coupled with low remarriage prospects⁹ for older widows with children, limited the percentage of women in the population with the opportunity to reproduce at older ages.

Duncan Gillespie, from the university's Department of Animal and Plant Sciences said that in today's society however, women do not start childbearing until an older age as marriage is often delayed.

He said: "As a result of this, the natural selection maintaining young-age fertility might weaken and the relative strength of natural selection on old-age fertility could increase, something that could potentially lead to improvements in old-age fertility over many generations.”

科学家指出，现在的晚育趋势将让未来女性40岁以后的生育能力增强。

许多女性会等到年龄很大时才生育，而只有那些带有更持久的繁殖基因的女性才会成功晚育。

这意味着生育能力持续的平均时间会随着她们的基因遗传给下一代而变长。

谢菲尔德大学的研究显示，以往女性会早早结婚，如果丈夫死了，她们也会因为年纪太大而无法再嫁，因此以前的女性会更多地早育。

不过现在的女性都不愿意早早安定下来，想晚一点再生育，这会使年纪较大的女性的生育能力也开始增强。

研究者追踪调查了1591位女性的生命史和婚史，研究了她们的婚姻模式。

研究数据来自19世纪和20世纪期间芬兰人的记录，在这个年代几乎所有人都结婚，离婚是被严格禁止的。

他们发现年龄在30岁到35岁之间的女性最有可能结婚。那些嫁给有钱人的女性结婚时间更早，不过丈夫的年纪相对较大，这意味着家庭人数更多，但是成为寡妇的几率也增加了。

研究者说女性成为寡妇的高几率，加上带着孩子的高龄寡妇再婚可能性很低，这使高龄产妇在人口中所占的比例受到限制。

来自谢菲尔德大学的动植物科学系的邓肯?吉莱斯皮说，然而，在今天的社会，因为结婚时间通常被推迟，所以女性到年纪较大时才生育。

他说：“因此，年轻生育的自然选择规律会减弱，而高龄生育的自然选择规律则会相对增强，这可能会导致未来很多代人的高龄生育能力增强。”

1 lasting   

adj.永久的，永恒的；vbl.持续，维持

参考例句：

• The lasting war debased the value of the dollar.持久的战争使美元贬值。
• We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。

2 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

3 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

4 wed   

v.娶，嫁，与…结婚

参考例句：

• The couple eventually wed after three year engagement.这对夫妇在订婚三年后终于结婚了。
• The prince was very determined to wed one of the king's daughters.王子下定决心要娶国王的其中一位女儿。

5 reluctance   

n.厌恶，讨厌，勉强，不情愿

参考例句：

• The police released Andrew with reluctance.警方勉强把安德鲁放走了。
• He showed the greatest reluctance to make a reply.他表示很不愿意答复。

6 strictly   

adv.严厉地，严格地；严密地

参考例句：

• His doctor is dieting him strictly.他的医生严格规定他的饮食。
• The guests were seated strictly in order of precedence.客人严格按照地位高低就座。

7 aged   

adj.年老的，陈年的

参考例句：

• He had put on weight and aged a little.他胖了，也老点了。
• He is aged,but his memory is still good.他已年老，然而记忆力还好。

8 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

9 prospects   

n.希望，前途(恒为复数)

参考例句：

• There is a mood of pessimism in the company about future job prospects. 公司中有一种对工作前景悲观的情绪。
• They are less sanguine about the company's long-term prospects. 他们对公司的远景不那么乐观。