If inflation is putting the squeeze on the average American family of four, imagine what it is doing to the Seeleys of Alexandria. With 11 children, making ends meet is something of a lost cause at the Seeley house.

The story of the Seeley family and how it grew began with a plan. Nine years ago, Jo Ann and Jim Seeley had four children. The plan was to adopt two more children and then call it quits.

In March 1970, two years after the birth of their fourth child, the Seeleys adopted seven-month-old Gretchen.

Then the plan began to break down. The year after Gretchen's adoption, Jo Ann Seeley gave birth to John. Then in 1973, they adopted a baby, Melissa. Just a year later, on New Years's Eve 1974, they adopted 4-year-old Christopher.

With Christopher's adoption, the Seeleys already had two more children than they had planned. As Jo Ann now recalls with a laugh, "That was another time we thought we were finished."

The next year -- 1975 -- the agency that had arranged Gretchen's adoption called the Seeleys. Could they find room for a five-year-old? The next day Jim picked up Todd.

Three years later Jo Ann gave birth to Michelle, and two summers ago the Seeleys adopted Carrie, who, so far, is the last addition to the family.

Asked why she became the mother of 11 children, Jo Ann shrugs and replies, "Why not? The kids were there and we enjoy them."

She pauses, then offers another explanation. "I have a friend who says I did all this as a neurotic compulsion . . . I had an extremely traumatic childhood.Maybe I get a vicarious thrill out of seeing kids who are not in a secure situation, in a secure situation."

Jim's only explanation is that it has "felt good every step of the way because it's worked and we haven't had to give up on our own relationship."

So there are the Seeleys: Jim, 16; Jenny, 15; Cindy, 14; Carrie, 12; Kevin, 11; Gretchen, 10; John, 8; Melissa, 7, Christopher, 9; Todd, 9, and Michelle, 3.

Looking down the line of Seeley children, one finds a mixture of ethnic backgrounds -- black, white, Korean, Vietnamese. Not so visible, say the Seeleys, are the small and large triumphs some of the children have achieved.

Of the five adopted children -- Gretchen, Melissa, Christopher, Todd and Carrie -- several have had severe physical or psychological problems to overcome.

Melissa, for instance, was born with a heart defect and already had suffered one heart failure before her adoption at seven months. Thankfully, Jo Ann Seeley said, the heart condition corrected itself two years ago.

When Christopher came to the Seeleys at age 4, he weighted only 20 pounds. "Our pediatrician said he had never had any protein in his life," Mrs. Seeley said.

In a few months, however, Christopher had doubled his weight and now is a healthy and energetic youngster.

Some of the most perplexing problems involved Todd, who spent his earliest years in war-torn Vietnam. For the first few months after he came to live with the Seeleys, the sound of an airplane sent him diving for cover. He also had difficulty distinguishing between reality and fantasy.

After his new parents indulged his wish for a Superman costume, they found him perched 10 feet above the ground on their porch railing, ready to fly.The first time they took him swimming, he jumped into the deep end of the pool and simply sat on the bottom, staring up.

"He didn't have normal responses to situations," Jo Ann Seeley says. "He would grin very inappropriately. He was totally wild."

Now, after five years with the Seeleys, Todd seems to have adjusted well. He has undergone phsycological testing twice, and the Seeleys say the results confirm their impression that his progress has been "unbelievable."

In fact, even though Jo Ann and Jim have watched their children carefully for signs of adjustment problems, they find being in a large family seems to have a healthful influence. For the adopted children, especially, they say, the family's size seems to ease pressures that could lead to emotional problems.

"In a bigger family, the kid just sort of blends in with what's going on," Jo Ann explains. "It's really therapeutic. It makes the transition for the kids so much easier."

Although the family's racial and ethnic diversity may seem likely to present problems, the Seeleys say they find finances the biggest challenge. The weekly grocery bill is about $160. The tab for utilities in a household that does five loads of laundry a day puts another strain on the $37,000-a-year salary Jim earns as a lobbyist for the City of Los Angeles.

To keep their eight-bedroom home going, Jo Ann assigns everyone a daily and weekly chore. The Seeleys' oldest daughter, Jenny, helps her mother keep the household in shape.

"It's not exactly 'House Beautiful,'" laughs Jo Ann, who says she is more interested in playing with her children than in keeping a perfectly run house.

For their part, the children agree unanimously that a large family is just the place for them.

"Sometimes it's crowded, but you always have people to play with and talk to," says 14-year-old Cindy.

The children do have one request: They want another brother to even things up at six boys, six girls.

Although Jo Ann and Jim would like to indulge that wish, they have stopped adding to the family because of a shortage of funds.

Eleven-year-old Kevin, however, is undaunted by financial restraints.

"It's cheaper by the dozen," he suggests cheerfully.