Kathleen and John Gagne, a baby boom generation couple, bought their first home in a sprawling new development in southwestern Fairfax County early this year. The "mid-$80,000" price tag was easily manageable on their combined incomes.

The Gagnes are among the "yuppies," or young, upwardly mobile professionals, the top one-third of their generation economically. John Gagne is moving up the management ladder at GTE Telenet, which transferred him to Northern Virginia this year. His wife will go back to work full time as an editor when their first child, two-week-old Sarah Nicole, is a few months older.

Their new home is small, at 1,320 square feet, but it sits on a corner lot. Across the road is a swimming pool and not far from their back door are soccer and baseball fields, which they were told will not be developed.

John Gagne said the house is well built of "good materials," and the builder "has been relatively good about repairing things" during the one-year warranty period. It is near Reston, where his company will move soon.

He earns between $40,000 and $50,000 as head of purchasing department for GTE Telenet in three locations and managing staffs in Mount Laurel, N.J., and in Vienna. When his wife works full time she earns in the "low-$20,000" range, she said.

The Gagnes were shocked by the price tags on houses they saw when they were home-hunting in Fairfax and the kinds of structures those prices would buy.

"Space-wise you don't get the amount of space you could have 20 years ago, or even five years ago," for the same amount of money, said Kathleen Gagne. "Construction-wise, it's hard to say. There have been improvements" in building techniques and materials. "It's probably true houses are less well built, but there are a lot of pluses too."

For the price of their Fairfax house, "we could probably get an eight-room house" in New Jersey, she said. In fact, the couple looked at one New Jersey house, a 15-room, old Victorian that needed "minor work." It sat on an acre of land in a rural area not for from his job and was priced at $82,000, said John Gagne.

When they were house-hunting "we first looked at town houses but we really wanted a house," his wife said.

"I am not as interested in the house as much as I am in the plot of land, which will be there forever," he added.

He doesn't expect to own the house more than about three years, however, in part for "job-related reasons. I will be in the position I'm in now for about three years. From then, we may be in this area or we may not be."

The couple fits a pattern demographers say characterizes most of the baby boomers, who are having only one or two children. "Right now we're all right with one," he believes. Both said that whether they will have another baby depends on what they decide they want to accomplish and what they want to give their children.

"Right now we're all right with one," he said. "We'll see what the cost of college is when she is 5 years old.