LEAD: Couples who circumvent public and private agencies to adopt a baby independently have become part of an increasingly self-protective institution with its own advocacy groups, its own protocol and its own lawyers.
Couples who circumvent public and private agencies to adopt a baby independently have become part of an increasingly self-protective institution with its own advocacy groups, its own protocol and its own lawyers.
About half of the healthy infants adopted in the United States are now placed independently, according to the National Committee for Adoption, a Washington umbrella group for 141 agencies that this week issued the first survey on adoption published in four years. Although the number of private adoptions has remained about the same since 1982, the techniques used have changed. Elaborate Instructions
These babies are adopted by all kinds of people - something that adoption lawyers hasten to point out - but more often than not the new parents are college-educated, urban residents in their 30's, securely married, well organized and accustomed to directing their own lives.
And that is what they do in bypassing adoption agencies, thus avoiding rejection or being placed on long waiting lists. In consulting the lawyers who have made a business of helping prospective parents, they find a better reception and, if they need them, elaborate instructions on how to advertise, distribute resumes and do whatever else is necessary to find a healthy baby.
The trend toward salesmanship - enticing advertisements and photos of the couples' houses and pets - worries the national adoption committee and other social-service professionals.
''This is not a resume-writing contest,'' said Dr. William L. Pierce, the committee's president. Unsentimental social workers, he said, may choose the same adoptive parents the birth mother would, and then again they may not. ''But they want to choose people who will be wonderful parents,'' he said.
Adoptive parents, overjoyed with their babies and usually grateful for whatever contacts they have had with the biological mothers, say they have every right to make such important choices on their own. They and their lawyers also say they are undercutting baby brokers who find pregnant young women, often deceiving them or coercing them into giving up their babies and then charging waiting couples $30,000 or more. Paying Expenses
Many pregnant women would rather not deal with an agency. An adopting couple will usually pay more of a birth mother's expenses than an agency can. Many of these women do not care to be questioned by social workers, and perhaps most important, while agencies are more and more willing to give a birth mother some voice in choosing adoptive parents, most will not allow her to talk to them.
The costs of an ordinary private adoption are not much higher than what an agency adoption would cost, and in some cases the costs may be about the same. In New York, the total for legal, medical, advertising, telephone and travel expenses is typically $8,000 to $12,000. That amount can soar if there are medical complications, and any money spent cannot be recovered if the birth mother changes her mind.
The private-adoption process can be painful and frustrating, especially in the 5 percent to 20 percent of the agreements that fall through. But the drawbacks cited so often by social-service professionals are primarily for the pregnant woman, who may not receive any counseling and does not have the safeguards that agencies provide. And in an illicit placement, of course, the danger is to the child. A Plea for Licensing
''If a lawyer wants to do adoption placement, let the lawyer be licensed by the state,'' said Sanford Katz, a professor at the Boston College Law School. ''After all, if you want to sell real estate, you have to get a broker's license.''
It is hard to know how many children are adopted, although every adoption must be approved and recorded in court, and it is harder still to know how the adoptions are arranged. The Federal Government stopped keeping national records 15 years ago, and the National Committee for Adoption arrives at estimates from figures it gathers from each state.
It was in the 1970's, as the number of available babies plunged, that agencies focused increasingly on older children, so couples wanting healthy infants turned to other avenues. By 1982, only half of the infant adoptions were handled by agencies, by the national adoption committee's estimate, a percentage that has remained fairly steady ever since.
What has changed is the way that couples in search of a baby go about it. Most who turn to private adoptions have already investigated agency adoptions and foreign adoptions, and then, frustrated, start advertising. Facing a 5-Year Wait
''I am not the sort of person to leave any stone unturned,'' said Julie W., an adoptive mother in Queens, who like most of the parents interviewed asked that her last name not be used to protect her privacy.
When an agency estimated a wait of two and a half to five years, Julie said, ''I nearly dropped my teeth.'' She then called a Brooklyn couple who had advertised an adoption service - the couple was later charged with conducting illegal adoptions -and was told, she said, that ''for a certain amount of money we can guarantee you a baby in a year.'' When Julie expressed reservations, ''they said, 'Well, you'll never get a baby on your own,' '' she recalled.
Finally, she and her husband consulted a lawyer and placed their own advertisements. ''Each and every time the phone rings you put your heart on your sleeve,'' Julie said. ''I flew to California to meet with one birth mother. She really wasn't sure what she wanted to do, and I found it very traumatic to go that far to be rejected.'' The Cost: $9,000 to $10,000
But within several months, the couple had already taken custody of a baby son, and a year later they had another son, both born to women who responded to the advertisements. The first adoption cost a little more than $10,000, the second $9,000.
Couples like Julie and her husband are motivated by desperation, resourcefulness and state law. New York does not permit any payment, except to a licensed agency, for finding or placing a child, and New Jersey forbids private intermediaries altogether.
Private adoption is illegal in a handful of states. The National Committee for Adoption urges stricter regulation, and some organizations, including the Child Welfare League of America, would prohibit independent adoptions altogether.
The New York Legislature tightened the state's adoption law earlier this year, after a grand-jury report in the case of Lisa Steinberg, the 6-year-old child beaten to death by Joel Steinberg, the lawyer who illegally kept the girl after he promised her birth mother to arrange for an adoption. The grand jury found ''serious problems in the manner in which provate-placement adoptions are regulated-or not regulated-in New York State.''
On Nov. 1, the state will begin requiring a home study before anyone takes custody of an infant, which was previously required only for infants born out of state. The new law also forbids a lawyer to represent both the birth mother and the adoptive parents.
Most parents and adoption lawyers have no quarrel with these restrictions but vehemently oppose proposals that would bring agency intervention. Even agency advocates acknowledge that many couples who would make excellent parents are turned down by agencies because of their age, religion or prior divorces. 'Playing God'
Tom J., a New York City schoolteacher who adopted a son privately several months ago, said he and his wife were both 39 when they approached two agencies. ''We found it to be - annoying would be the best way to put it,'' he said. ''They said if you were a certain age they wouldn't take you. To me that's playing God.''
''If you ever asked the general population to take tests for parenthood, there'd be riots,'' he added.
The couple started their own search after their lawyer, Michael S. Goldstein, provided a list of newspapers around the nation that accept adoption advertising. Mr. Goldstein also advises clients on how to ask and answer questions in conversations with the pregnant young women who answer the ads.
Mr. Goldstein said that ''of the couples who don't have a line on a kid already, just about everybody places some kind of advertisement.'' Are the couples reluctant? ''Sure they are,'' he said. But that is how at least two-thirds of his clients find babies, usually within a year.
Adoption advertising is illegal in 19 states, and most large newspapers do not accept such advertisements. But through shoppers' weeklies, college newspapers and some national publications, from USA Today to Rolling Stone, a couple can blanket the nation.
''Eight or nine years ago it was a strange thing to do,'' said Blanche Gelber, a Manhattan adoption lawyer. ''Today it's commonplace.''
Some lawyers still find it strange. ''Why would a mother give up her baby to somebody who put an ad in a paper?'' said Nicholas Stevenson, a Chicago lawyer who handles 50 to 70 private adoptions a year. ''It always shocks me.''
But to those who say the advertisements are exploitative, Robin Fleischner, a Manhattan adoption lawyer, said: ''I find that a repulsive statement. It's not about money. With ads, the birth parents try to find a family that suits their needs and values.'' No to Baby-Selling
The one evil that everyone agrees on is baby-selling, although there is little agreement on exactly what that is. Many states permit adoptive parents to pay the birth mother's reasonable living expenses during her pregnancy. But these must be approved -after the fact - by the judge in charge of the adoption proceedings.
Although prosecutions are rare, lawyers concede that unreported cash does change hands. Many adoptive parents say they received requests for extra money for the birth mothers, and while reputable lawyers would not approve of this, some lawyers make the requests themselves.
A 1978 study of independent adoption by Professor Katz of the Boston College Law School found that 1 in 7 couples suspected that their adoptions had involved some illegal activity.
Dr. Pierce, the president of the National Committee for Adoption, said illegality was only one of many risks involved in private adoptions.