Some demographers say the United Nation's world population statistics just don't add up. Specifically, they are questioning projects that put the world population total at 9.4 billion by 2050 -- a 62 percent increase above what it is today.

Here are some of their objections:

• With birth rates and fertility rates in many areas around the world having fallen to their lowest levels in decades, the U. N. may be projecting as many as 3 billion extra people on the planet at the middle of the next century.

• Although it takes 2.1 children per woman simply to maintain a stable population over time, fertility rates in Europe are now at an incredibly low 1.45 children per woman -- a decline of 21 percent just in the last decade.

• Japan's rate is 1.5 and the Italian rate is 1.2 -- said to be the lowest rate in the history of the world.

• The U. S. rate has declined in each of the last six years -- to an estimated 1.98.

In the last 30 years, the aggregate rate in the less developed countries has plunged from 6.0 to 3.1 children per woman -- with the most dramatic drop occurring since 1990.

With a current world population of about 5.8 billion, the U. N. is also predicting that figure will climb to 10.7 billion just after the year 2200 -- an increase of 84 percent.

With fertility rates falling so dramatically now, demographers admit themselves baffled by the U.N.'s off-the-wall increases.

Source: Ben Wattenberg, "Population Data that Doesn't Compute," Washington Times, March 27, 1997.