Population growth's older face is likely to influence housing market.

California's population growth never seems to change much--a half-million more people per year, give or take. But where all those people come from and what the growth means for the future of the state are always changing.

Here's a good example, courtesy of demographer Hans Johnson of the Public Policy Institute of California: During the 1990s, California added 4 million people--but only 60% of them (2.5 million) were adults, while 40% (1.5 million) were children. In the first decade of the 21st Century, we're looking at adding about 5 million people. But this time around, 90% of them (4.5 million people) will be adults and only 10% (500,000) will be children.

The reason is simple: The vast increase in Latino population during the 1990s was due largely to extremely high Latina fertility rates that are typical of first-generation immigrants. But Latina fertility rates are decreasing, and all the Latino kids born during the '80s and '90s …