The teen birth rate has fallen steadily since 1991. But demographers caution that the number of teen-age girls in the population is set to rise dramatically in the next decade. Will that precipitate another upward swing in babies born to unwed teen mothers?

• Since 1991, the teen birth rate has dropped by about 14 percent -- to 54.4 births for every 1,000 teen-age girls.

• Among black teen-age girls the decline has been even more dramatic -- a decline of 21 percent since 1991, to 91.4 births per 1,000.

• The number of youngsters entering their teens began to rise in 1995, however, and by 2010, there will be 2.2 million more girls ages 15 to 19 than there are now.

• If tomorrow's teens have children at the same rate they are having them now, the number of teen births will jump by 26 percent.

Experts say that breaking the cycle of teen parenthood may be the key to reducing the number of children in poverty. Babies born to teen-agers are much more likely to face additional risks -- from poverty to health troubles to poor school performance to becoming parents, themselves, when they reach their teens.

There is apparently a small, but important, trend among youngsters toward less casual sex. Moreover, those who are active report they are using birth control devices more frequently than their predecessors did.

Source: Anna Bray Duff, "Behind the Drop in Teen Births," Investor's Business Daily, February 11, 1999.