The US fertility rate has just hit a historic low. Some demographers are freaked out.

The US fertility rate has just hit a historic low. Some demographers are freaked out.

The United States are in the middle, which is some worries of a baby crisis. The number of births has declined for years and has just hit a historic low. If the trend continues - and the experts do not agree, whether the country is facing economic and cultural unrest.

According to the preliminary 2016 population data released by the centers for disease control and prevention on Friday, the number of births fell by 1 per cent from a year before, bringing the overall birth rate to 62.0 births per 1,000 women aged 15 to 44 The trend is driven by a decline in birth rates for adolescents and 20-somethings. The birth rate for women in their 30s and 40s increased - but not enough to lessen the lower numbers in their younger counterparts.

The birth rate of a country is one of the most important measures of demographic health. The figure must be within a certain range, called "replacement level", in order to keep a population stable so that it neither grows nor shrinks. If too low, there is a risk that we will not be able to replace the aging workforce and have enough tax revenues to keep the economy stable. Countries like France and Japan, which have low birth rates, have set pro-family policies to try to encourage couples to have babies. The flip side can also be a problem. Births that are too high can weigh resources such as clean water, food, shelter and social services, problems with India, where the fertility rate has fallen in the past decades but still remains high.

The debate is about whether the United States is being led by a "national emergency," as some have feared, or whether it is a blip, and the birth rate will soon be cut off.

"It's about a thousand years," says Donna Strobino, a professor of population, family and reproductive health at the Johns Hopkins Bloomberg School of Public Health.

Those who claim to be young adults with fragile egos who were born in the 2000s living in the cellars of their parents and bouncing from job to job turns out to be much less likely to babies To have at least so far. Some experts think that Millennials only shift parenthood, while others fear that they will choose not to have children at all.

Strobino is among those who are optimistic and see the hope in the data. She points out that the case of birth rates in adolescents - an age when many pregnancies tend to be unplanned - is something we want and that the highest birth rates among women are now 25 to 34 years old.

"What that is is a trend of women who are becoming more educated and mature, I'm not sure this is bad," she said.