Utah's birth rate has declined slightly since 1980, but the state remains the nation's "most extreme" example of fertility, with a rate higher than the People's Republic of China, according to Population Today magazine.

By the next century, demographers said in the magazine article, Utah's population should be double that of Massachusetts, where the declining fertility rate is lower than that of the Netherlands.States with low birth rates will have a declining number of workers and a larger aged population to care for, while states with high fertility rates will have to shoulder the burden of paying for children's educations.

By 1986, birth rates were estimated to have decreased in Utah to 2.6 children per woman, from the 1980 level of 3.2. The "replacement level" is about two children per woman.

But even if the rates decline to 2.5 by 1990, as many state officials suggest, the state's population will climb past that of Massachusetts during the next century until it is more than twice the Bay State's, according to the article.

In the United States, birth rates have been below the "replacement level" of two children per woman for many years. In 1987, the nation's fertility rate was 1.88.

The magazine, produced by the Population Reference Bureau, gave no prediction of when, if ever, Utah's population would decline. However, the article said a state's fertility patterns and life expectancies rarely change.

The U.S. Census Bureau predicts deaths may begin to outnumber births in this country around 2030 or 2035. Immigration may offset natural population decreases, but eventually the population will begin to shrink.

A declining population is good news for entry-level workers, but bad news for "low fertility" states, which will have to contend with the needs of the aged and a shrinking tax base.

So far, no state's population has ever declined as a result of more annual deaths than births, according to the article.

However, labor-force shortages plague some areas today. Some companies in New Hampshire are scrambling for workers and fast-food chains are paying more than twice the minimum wage.

Utah must contend with a different problem. The Census Bureau lists the state last in the nation in the percent of population age 18 or older - those who pay taxes. Thus, Utahns spend a higher share of the state's budget for education but fall last or next to last in the nation in per-pupil expenditures for children in school.

Factors influencing the level of child bearing in Utah include The Church of Jesus Christ of Latter-day Saints, members of which compose about 70 percent of the state's population.