Calvin Beale, senior demographer of the Economic Research Service at the federal Department of Agriculture, said: "After age 75, as health diminishes and/or widowhood occurs, there is some measure of return flow back to areas of origin, or wherever a caretaker-minded son or daughter lives.

Carl Haub, a senior demographer for the Population Reference Bureau, a research group, concurred that the 300 millionth American is likely to be male - more boys are born than girls - and generally agreed with Dr. Frey about the baby's other characteristics, but left more wiggle room.

"There's something in the Irish attitude that says, 'I belong in America,' " said Francis P. Vardy, senior demographer in the Department of City Planning who closely follows the Irish migration patterns.

And Frank Vardy, a senior demographer with the City Planning Department, said the actual number could be significantly higher.

Fifty acres of forest are lost every day in the Atlanta area alone, and Calvin L. Beale, senior demographer with the United States Department of Agriculture, said about two million acres of farmland are being developed every year.

India's experience highlights the link between population growth and economic advancement in poor countries, said Carl Haub, the senior demographer at the Population Reference Bureau, a nonprofit research group.

Poverty has also swallowed more children, with about 16.4 million in its ranks last year, the highest numbers since 1962, according to William Frey, senior demographer at Brookings.

Since 1980, more than 800,000 Caribbean immigrants have moved to New York, not counting those illegally in the city, according to Frank P. Vardy, a senior demographer in the City Planning Department.

Calvin Beale, senior demographer in the Agriculture Department, said that each decade about 200 previously incorporated towns across the country fail to show up in the census, although he said there was no way to know from the statistics why the town governments disbanded.

Now Towns Look to Retirement "Some towns that might have gone after a shirt factory before to boost their economy are now looking for retirement communities," said Calvin Beale, a senior demographer at the United States Agriculture Department who follows rural population trends.