PBS高端访谈:美国低出生率背后的故事（在线收听）

JUDY WOODRUFF: Birth rates in the USA have dropped to their lowest annual levels in three decades, falling for nearly every group of women, and part of a longer decline that dates back to the Great Recession. Amna Nawaz looks at some of the reasons why this may be happening.

AMNA NAWAZ: More than 3.8 million babies were born in the United States last year. But last year's drop in the nation's birth rate, about 2 percent overall, was the largest drop in a single year since 2010. The rate even fell slightly for women in their 30s. And the teen birth rate continued its dramatic nosedive since the early '90s, down 55 percent since 2007. Last year, the only group to see a higher birth rate was women in their 40s. All this amid some concerns about America's aging population. Hans-Peter Kohler, who studies fertility and birth rates in this country and many others at the University of Pennsylvania, joins me now. Dr. Kohler, thank you so much for making the time. Let me ask you about these numbers now, the lowest number of recorded births in 30 years, the largest single drop since 2010. It paints a pretty grim picture. Is it?

DR.HANS-PETER KOHLER, University of Pennsylvania: So, this report is big news, and, on the other hand, not all that surprising. So, the U.S. stood out among high-income countries as one that had relatively high fertility. And the Great Recession changed that, and across many high-income countries, the recession resulted in declining fertility rates. The really surprising part is that we have now been quite some years through the recession, and unemployment rate is very low, and that trend hasn't changed. So these low fertility rates, despite relatively good economic conditions, are really surprising. I wouldn't argue that they're a disaster or particularly worrisome. I would argue that the U.S. demographics in general continue to be relatively healthy, at least compared to many other high-income countries.

AMNA NAWAZ: So, let's talk about the economic anxiety part of this. So obviously, a lot of people point toward that as a theory why the birth rate declines. But, as you mentioned, we're out of a recession now. So, how do you look at these numbers? How do you explain this decline?

DR.HANS-PETER KOHLER: So, presumably, a big part is driven by a delay of childbearing. So, there have been big declines in teenage fertility rates, and that is good news, because that presumably indicates a big decline in unintended or mistimed pregnancies. And across adult ages, that's presumably a delay of childbearing resulting from, on one hand, a desire to have children at later ages, often perhaps pressured by economic stress in early adulthood, or high housing prices, or desires to actually invest in child quality. And so these trends combine into a pattern where fertility and parenthood is going to be increasingly later. That's going to be across the board. And the U.S. shares this across many high-income countries.

AMNA NAWAZ: A lot of people sometimes float a theory about immigration playing a role in birth rates increasing or declining. Tell me about that.

DR.HANS-PETER KOHLER: I don't immigration has a big factor in this story. So, immigrant fertility adjusts relatively quickly to the U.S. native fertility. And I don't think changes in immigration policy, immigration flows had a big contribution to these recent declines in total fertility rates.

AMNA NAWAZ: So, Dr. Kohler, tell me why we care so much about birth rate. Obviously, people will pay attention to these numbers. They will note these declines. But what do the numbers say about the health or trajectory of America right now?

DR.HANS-PETER KOHLER: Many would see the number of children as an indicator of the well-being of the adult population, from the notion that individuals who are satisfied with their life and have relatively good economic prospects are more likely to have children. The other reason we care about this is that children born today are obviously the workers 25 years down the road and are retirees some 60, 70 years down the road. And so the number of birth is going to shape the overall size and structure of the U.S. population, and that has a magnitude of implications on both the economic situation and social situation of the United States. So, in the long term, if this trend persists, they're going to have profound implications. And the annual number of birth probably has relatively small implications.

AMNA NAWAZ: So, Dr. Kohler, you mentioned these numbers aren't terribly surprising to you. They're also not terribly worrisome right now. At what point do you start to get worried?

DR.HANS-PETER KOHLER: Well, if we compare the U.S. to other high-income countries, we could see that fertility could drop a lot lower. So, total fertility rates dropped to rates like 1.2 in many Southern European countries. They're at these levels in South Korea, and were at somewhat higher levels in Japan. So, on one hand, there's quite a bit of possibility for further decline, further declines in fertility. And once we get to very low fertility, or what I have called lowest low fertility, at some point, then the kind of implications of rapidly aging populations and possibly declining labor force become very difficult to manage through social policies.

AMNA NAWAZ: Dr. Hans-Peter Kohler at the University of Pennsylvania, thank you for your time.

DR.HANS-PETER KOHLER: You're most welcome.

朱迪·伍德拉夫：美国的出生率已经降到了三十年来的最低水平，几乎每一组别的女性都在下降，而部分更长期的下降则要追溯到大萧条时期。阿姆纳·纳瓦兹看可能发生这种情况的原因。

阿姆纳·纳瓦兹：去年美国新生婴儿数量超过380万。但去年全国出生率总体下降了约2%，为自2010年以来的最大年度降幅。对于30岁组别的女性来说，这一比率甚至更低。自上世纪90年代初以来，青少年生育率持续大幅下降，自2007年以来下降了55%。去年，唯一出现较高出生率的群体是40岁组别的女性。而这些现象让一些人对美国人口的老龄化产生担忧。宾夕法尼亚大学的汉斯·皮特·科勒对这个国家的繁殖力及出生率等诸多方面进行了研究，现在他加入节目。科勒博士，非常感谢您能抽出时间。现在关于这些数字，让我问问您，30年来记录的最低出生率，2010年以来的最大单次降幅。它描绘了一幅非常可怕的图景。是不是？

汉斯·皮特·科勒博士，宾夕法尼亚大学：所以，这份报告是个大新闻，而另一方面，却并不是那么出人预料。那么，美国过去在高收入国家中表现突出，其生育率相对较高。大萧条改变了这种趋势，在许多高收入国家，经济衰退导致了生育率下降。令人惊讶的是，我们的经济衰退已经过去好几年了，失业率很低，但这一趋势却没有变化。因此，尽管经济条件相对较好，这些低生育率确实令人感到惊讶。我并不认为，这是一种灾难或者需要特别担忧。我会认为，美国人口统计总体上仍然相对健康，至少与其他许多高收入国家相比是这样。

阿姆纳·纳瓦兹：那么，让我们来谈谈这方面的经济焦虑。显然，很多人把这一理论归为出生率下降的原因。但是，正如你提到的，我们现在已经走出了衰退。

那么，你如何看待这些数字呢？你如何解释这种下降？

汉斯·皮特·科勒博士：那么，大概，很大一部分是由生育延迟引起的。因此，青少年生育率大幅下降，这是个好消息，因为这可能意味着意外怀孕或不合时宜的怀孕，大幅度下降了。而在成人期，这大概是由于生育的延迟，一方面是人到晚年，想要孩子，可能也是由于成年初期的经济压力，或是高房价，或是希望实际高质量地投资于孩子。因此，这些趋势与繁殖力及生育越发延迟的模式相互结合。这将涉及各个方面。美国和许多高收入国家都存在这种情况。

阿姆纳·纳瓦兹：很多人有时会将关于移民的理论应用到人口出生率的上升和下降上。给我讲讲这些。

汉斯·皮特·科勒博士：我认为移民在这件事上并没有起到太大的影响作用。因此，移民的生育率相对较快地适应了美国当地的生育能力。我认为移民政策和移民流的变化对最近的生育率下降并没有产生很大影响。

阿姆纳·纳瓦兹：那么，科勒博士，请告诉我，为什么我们对人口出生率如此关心。显然，人们会关注这些数字。他们会注意到这些下降。但是，关于美国目前的健康状况，这些数字是怎么说的呢？

汉斯·彼得·科勒博士：许多人会认为儿童的数量是衡量成年人口幸福度的一个指标，那些对自己的生活感到满意、经济前景较好的人更容易生孩子。我们关心生育率的另一个原因是，今天出生的孩子显然是25年后的生产力，60年 70年后的退休人员。因此，出生人数将决定美国人口的总体规模和结构，这对美国的经济形势和社会状况都有重大影响。因此，从长远来看，如果这种趋势持续下去，它们将产生深远的影响。而每年出生人数的影响可能相对较小。

阿姆纳·纳瓦兹：所以，科勒博士，你提到这些数字对你来说，并不感到惊讶。现在也不太担心它们。那么要到什么时候才需要开始担心呢？

汉斯·彼得·科勒：嗯，如果我们把美国和其他高收入国家作比较，我们可以看到生育率会下降很多。因此，在许多南欧国家，总生育率下降到1.2。韩国也维持在这个水平，日本则稍高。因此，一方面，进一步下降的可能性很大，生育率进一步下降。一旦我们的生育率达到非常低的程度，或者在某种程度上，我称之为最低的低生育率，那么迅速老龄化的人口和可能下降的劳动力所带来的影响，将变得非常难以通过社会政策来进行管理。

阿姆纳·纳瓦兹：宾夕法尼亚大学的汉斯·彼得·科勒博士，谢谢您宝贵的时间。

汉斯·彼得·科勒博士：您不用客气。