Boston — Thirteen years ago when Jean and Frank Nagle of Arlington, Mass., decided to adopt an older brother for their two natural daughters, aged 3 and 5, they encountered resistance from the state adoption placement unit. ''At the time they fought the idea of adopting an older child,'' recalls Mrs. Nagle, although the family eventually succeeded.
A few years later, when they applied to adopt a second son, the reception was totally different. The Nagles became one of the first families to work with Project Impact, an organization designed specifically to help place older and ''special needs'' children. These include children over 7, sibling groups, minority children, and those with emotional, intellectual, or physical handicaps.
Today, with an estimated 50,000 children, most of whom are considered special needs children, legally available for adoption in this country, there is a crucial need for more families to provide permanent, loving homes.
''People have stretched and changed in their view of the children they could parent,'' says Robert Lewis, director of Project Impact. ''(Adopting a special-needs child) is not an easy thing to do by any means, but it's a real growing experience for parents.''
Adoption agencies and exchange services are also changing their perceptions about what makes a child adoptable. Because there are very few white infants available for adoption, more effort is devoted to finding homes for children who have traditionally been considered hard to place.
''We go by the philosophy that no child is unadoptable,'' says Deborah Burke, communications specialist of the Massachusetts Adoption Resource Exchange (MARE). ''More and more people are looking to adopt older and 'special needs' children because infants and toddlers are so hard to come by. Adopting a healthy white infant can take from three to seven years.''
For parents willing to take on the sometimes arduous adoption process, there are options. Related children, for example, are one of the larger groups available for adoption.
''People who are interested in building a family sometimes choose sibling groups because they are already emotionally connected. That is a real asset in people's minds,'' Miss Burke says. Prospective adoptive parents are also attracted to groups of siblings because they can find younger children at preschool ages.
Deborah and William Huegel of Winchester, Mass., adopted a brother and a sister 41/2 years ago when the children were 41/2 and 51/2 years old.
''I don't think adopting siblings is too different from adopting a single child, except you have to get used to more people and more interactions at one time,'' Mrs. Huegel says. ''It's very good to see the changes in the children that can be made by a permanent, disciplined, loving environment. That's very rewarding.''
The Huegels are in the process of adopting another sibling group of three brothers who have been living with them in foster care for more than two years. In Mrs. Huegel's view, the case has been unnecessarily caught up in the courts, pending a decision about the children's legal status.
''The delays definitely take a toll on the kids and are frustrating for us,'' Mrs. Huegel says, especially since the youngest of the three brothers is already 41/2. ''It's difficult for (the boys) to settle in when things are still up in the air and have not been legalized.''
Deborah Burke also cites the increasing numbers of couples with grown children who start second families by adopting older children.
''These people are experienced parents who can offer a lot to these children because they have been through it before,'' she says. ''They recognize children need a support system no matter what their age.''
Locating children available for adoption can be a challenge for potential parents. Some work through state and private adoption agencies; others have turned to adoption ''exchanges,'' which match waiting families with waiting children.
Moving into its 26th year, MARE is one of the oldest and largest of the 30 adoption exchanges across the country. In addition to working with the 40 licensed adoption agencies in Massachusetts, MARE functions as an informal exchange for the six New England states. It is also the first exchange to open a branch: the Ocean State Adoption Resource Exchange in Providence, R.I.
Through contacts with social workers in adoption agencies around Massachusetts, MARE registers children waiting for homes and maintains a similar listing of families who have been approved for adoption and are looking for children. Listing coordinators look for possible matches between waiting children and waiting families. If a match seems right, the child's social worker is contacted. In 1982, MARE was directly responsible for creating 117 matches between children and adoptive families.
If an immediate referral cannot be made, the child is listed in the MARE Manual, in which a child is featured on each page with a photograph and a short biography. The books are placed in more than 300 locations around Massachusetts, including community centers, public libraries, and churches. Creative recruitment for families
''Most adoption agencies do not have the the budget to recruit families,'' says Miss Burke. Like exchanges in many other cities, MARE uses both newspapers and television to let the public know about children who need homes. According to Miss Burke, the organization is trying to encourage more minority families to adopt children.
MARE and Project Impact also collaborate on a relatively new recruitment idea: adoption parties. At these gatherings, children waiting for a permanent home have the opportunity to meet prospective adoptive parents (who have passed agency screenings) in a relaxed, informal atmosphere.
''The parties have turned out to be wonderful resources for everyone in many ways,'' Miss Burke says.
MARE makes a special effort to work with newcomers and has recently opened the parties to families interested in adoption who have not yet gone through the screening process with a state or private adoption agency. Staff members help educate potential adoptive parents about the realities of the adoption system. A home study in which the social worker evaluates the home and parents' suitability for a particular child or children, for example, can take three or four months. MARE also advises parents not to harbor unrealistic expectations about finding the ''ideal child.''
''We encourage people to look at everything - read information, talk to parents who have adopted children - so they can make the best decision for themselves,'' Miss Burke says. ''Sometimes the best decision is not to adopt.''